Class X Science 2023-24 Learning Material PDF

SCIENCE MINIMUM LEVEL LEARNING MATERIAL for CLASS – X 2023 – 24 Prepared by M. S. KUMARSWAMY, TGT(MATHS) M. Sc. Gold Medallist (Elect.), B. Ed. Kendriya Vidyalaya gachibowli DEDICATED TO MY FATHER LATE SHRI. M. S. MALLAYYA MINIMUM LEVEL DAILY REVISION SYLLABUS FOR REMEDIAL STUDENTS SCIENCE : CLASS X S. NO. CHAPTER/TOPIC MARKS COVERED 1 Chemical Reactions and Equations 2 Metals and Non-metals – Full Chapter 20 marks 3 Carbon and its compound – Full Chapter 4 Life Process – Full Chapter 17 marks 5 Heredity 6 Our Environment – Full Chapter 5 marks 7 Magnetic Effect of Electric Current – 6 marks Full Chapter** Total Marks Around 48 marks ** Revised syllabus only (excluding deleted portion for 2022-23) All Remedial Students have to complete the above chapters/topics thoroughly with 100% perfection and then they can also concentrate the below topics for Board Exam: *Electricity – Imp questions and objective type questions *Light – Imp questions and objective type questions *The Human Eye and Colourful World – Imp questions and objective type questions *How do organisms reproduce – Imp questions and objective type questions *Acid, Bases and Salts – Imp questions and objective type questions *Control and Coordination – Imp questions and objective type questions INDEX OF MINIMUM LEVEL LEARNING STUDY MATERIAL CLASS X : SCIENCE S. NO. CHAPTER/CONTENT PAGE NO. Chemical Reactions and Equations Important Question Answers 1 1 – 17 and Objective type questions Metals and Non metals Important Question Answers and 2 18 – 34 Objective type questions Carbon and its Compounds Important Question Answers and 3 35 – 48 Objective type questions Life Processes Important Question Answers and Objective type 4 49 – 73 questions Heredity Important Question Answers and Objective type 5 74 – 80 questions Our Environment Important Question Answers and Objective 6 81 – 92 type questions Magnetic Effects of Electric Current Important Question 7 93 – 116 Answers and Objective type questions Electricity Important Question Answers and Objective type 8 117 – 133 questions Light – Reflection and Refraction Important Question Answers 9 134 – 159 and Objective type questions The Human Eye and Colourful World Important Question 10 160 – 168 Answers and Objective type questions How Do Organisms Reproduce Important Question Answers and 11 169 – 183 Objective type questions Acids, Bases and Salts Important Question Answers and 12 184 – 200 Objective type questions Control and Coordination Important Question Answers and 13 201 – 226 Objective type questions CHEMICAL REACTIONS AND EQUATIONS VERY SHORT ANSWER TYPE QUESTIONS [1 MARK] 1. In electrolysis of water, why is the volume of gas collected over one electrode double that of gas collected over the other electrode? Answer. It is because water contains hydrogen and oxygen in the ratio of 2 : 1. 2. Balance the following chemical equations. Answer. 3. What happens chemically when quicklime is added to water filled in a bucket? Answer. Quicklime reacts with water to form slaked lime and produces lot of heat and hissing sound. 4. On what basis is a chemical equation balanced? Answer. A chemical reaction is balanced on the basis of law of conservation of mass. 5. What change in colour is observed when white silver chloride is left exposed to sunlight? State the type of chemical reaction in this change. Answer. Silver chloride becomes grey. It is a photochemical decomposition reaction. 6. Write a balanced chemical equation for the reaction between sodium chloride and silver nitrate indicating the physical state of the reactants and the products. Answer. 7. State one basic difference between a physical change and a chemical change. Answer. In physical change, no new substance is formed, whereas in a chemical change, new substance(s) is/are formed. 8. What is meant by a chemical reaction? Answer. The reaction representing a chemical change is called a chemical reaction. 9. AgN03(aq) + NaCl(aq)——————– > AgCl(s)4↓ + NaN03(aq) FeS + H2S04————- > FeS04 + H2S↑ Consider the above mentioned two chemical equations with two different kinds of arrows (↑and ↓) along with product. What do these two different arrows indicate? Answer. ↑shows the gas is evolved whereas ↓shows insoluble substance (precipitate) is formed. 10. Hydrogen being a highly inflammable gas and oxygen being a supporter of combustion, yet water which is a compound made up of hydrogen and oxygen is used to extinguish fire. Why? Answer. It is because properties of compound (H2O) are different from properties of its constituting elements, i.e. H2 and O2. Prepared by: M. S. KumarSwamy, TGT(Maths) Page - 1 - SHORT ANSWER TYPE QUESTIONS [I] [2 MARKS] 11. Name the products formed on strongly heating ferrous sulphate crystals. What type of chemical reaction occurs in this change? Answer. It is decomposition reaction. 12. What is an oxidation reaction? Give an example of oxidation reaction. Is oxidation an exothermic or an endothermic reaction? Answer. The reaction in which oxygen or electronegative element is added or hydrogen or electropositive element is removed or loss of electrons takes place, is called an oxidation reaction, e.g. , Oxidation reactions are mostly exothermic in nature because heat is evolved in this process. 13. Describe an activity to demonstrate the change that takes place when white silver chloride is kept in sunlight. State the type of chemical reaction which takes place. Answer. Aim: To demonstrate the change that takes place when white silver chloride is kept in sunlight. Materials Required: AgNO3(aq), NaCl(aq), test tubes. Procedure: 1. Take 5 ml of silver nitrate solution in a test tube. 2. Prepare sodium chloride solution in another test tube. 3. Add sodium chloride solution into test tube containing silver nitrate solution. 4. Observe the colour of silver chloride formed chloride to grey silver metal Dry it with the help of filter papers and place it on the watch glass. 5. Place the watch glass under sunlight for sometime. 6. Observe the colour of the silver chloride after sometime. Observation: White silver chloride turns grey in sunlight because silver metal is formed. Explanation: Silver chloride is photosensitive. It decomposes in presence of sunlight to form silver metal and chlorine gas. Conclusion: Decomposition of silver chloride in presence of sunlight is photochemical decomposition reaction. Prepared by: M. S. KumarSwamy, TGT(Maths) Page - 2 - 14. When magnesium ribbon burns in air or oxygen, a product is formed. State the type of chemical reaction and name the product formed in the reaction. Write balanced chemical equation of this reaction. Answer. The type of reaction is combination reaction and the product formed is magnesium oxide. 15. Distinguish between a displacement reaction and a double displacement reaction. Identify the displacement and the double displacement reaction from the following reactions. Answer. Displacement reaction is a reaction in which more reactive metal can displace less reactive metal from its salt solution. Double displacement reaction are those reactions in which compounds exchange their ions to form two new compounds (i) Double displacement reaction (ii) Displacement reaction 16. When you have mixed the solutions of lead(II) nitrate and potassium iodide, (i) what was the colour of the precipitate formed and can you name the precipitate? (ii) write the balanced chemical equation for this reaction. (iii) is this also a double displacement reaction? Answer. (i) The colour of the precipitate is yellow. The name of compound formed as a precipitate is Pbl2 (lead iodide). (iii) Yes, it is also a double displacement reaction. 17. What do you mean by exothermic and endothermic reactions? Give examples. Answer. Exothermic reactions are those in which heat is evolved, e.g. Endothermic reactions are those reactions in which heat is absorbed, e.g. 18. What happens when an aqueous solution of sodium sulphate reacts with an aqueous solution of barium chloride? State the physical conditions of reactants in which the reaction between them will not take place. Write the balanced chemical equation for the reaction and name the type of reaction. Answer. White precipitate of barium sulphate is formed. If both reactants are in solid state, then the reaction will not take place between them. It is a double displacement as well as a precipitation reaction. 19. What is a redox reaction? When a magnesium ribbon burns in air with a dazzling flame and forms a white ash, is magnesium oxidised or reduced? Why? Answer. The reactions in which oxidation (loss of electrons) and reduction (gain of electrons) take place simultaneously are called redox reactions. Prepared by: M. S. KumarSwamy, TGT(Maths) Page - 3 - Magnesium is getting oxidised because it is losing electrons to form Mg2+ and oxygen is gaining electrons to form O2-, therefore it is getting reduced. 20. Write any two observations in an activity which may suggest that a chemical reaction has taken place. Give an example in support of your answer. Answer. Any two of these observations will suggest chemical reaction has taken place. (i) Change in state. (ii)Change in colour. (iii) Evolution of gas. (iv)Change in temperature. For example, lead nitrate is white crystalline solid which on heating gives yellowish brown solid (lead monoxide). A brown gas and a colourless gas is also evolved. It shows chemical reaction has taken place. 21. When the powder of a common metal is heated in an open china dish, its colour turns black. However, when hydrogen is passed over the hot black substance so formed, it regains its original colour. Based on the above information, answer the following questions. (i) What type of chemical reaction takes place in each of the two given steps? (ii) Name the metal initially taken in the powder form. Write balanced chemical equations for both reactions. Answer. (i) In first step, oxidation takes place. In second step, redox reaction takes place. (ii)Metal in the powder form is copper. 22. Using a suitable chemical equation, justify that some chemical reactions are determined by: (i) change in colour, (ii) change in temperature. Answer. 23. (a) A solution of substance ‘X’ is used for white washing. What is the substance ‘X’? State the chemical reaction of ‘X’ with water. (b) Why does the colour of copper sulphate solution change when an iron nail is dipped in it? Answer. (a) ‘X’ is calcium oxide (CaO). CaO(s) + H2O(l) —–> Ca(OH)2(aq) + heat (a) It is because iron displaces copper from CuS04 to form FeS04 which is pale green. Fe(s) + CUS04 (aq)—–> FeS04(aq) + Cu(s) Blue Pale green 24. Balance the following chemical equations. (a) BaCl2 + H2SO4 → BaSO4 + HCl (b) Ca(OH)2 + HNO3 → Ca(NO3)2 + H2O (c) Pb(NO3)2 → PbO + NO2 + O2 (d) MnO2 + HCl → MnCl2 + H2O + Cl2 Prepared by: M. S. KumarSwamy, TGT(Maths) Page - 4 - Answer. (a) BaCl2 + H2SO4 → BaSO4 + 2HCl (b) Ca(OH)2 + 2HNO3 → Ca(NO3)2 + 2H2O (c) 2Pb(NO3)2 → 2PbO + 4NO2 + O2 (d) MnO2 + 4HCl → MnCl2 + 2H2O + Cl2 25. Write the balanced equation for the. following reaction and identify the type of reaction in each case. (a) Potassium bromide + Barium iodide → Potassium iodide + Barium bromide. (b) Hydrogen (g) + Chlorine(g) → Hydrogen chloride (g) Answer. (a) 2KBr(aq) + BaI2(aq) → 2KI(aq) + BaBr2(aq) (b) H2(g) + Cl2(g) → 2HCl(g) 26. A zinc plate was put into a solution of copper sulphate kept in a glass container. It was found that blue colour of the solution gets fader and fader with the passage of time. After few days, when zinc plate was taken out of the solution, a number of holes were observed on it. (i) State the reason for changes observed on the zinc plate. (ii) Write the chemical equation for the reaction involved. Answer. (i) It is because zinc has displaced copper from CuS04. Zinc metal has been used to form zinc sulphate, therefore, number of holes were observed. 27. A white salt on heating decomposes to give brown fumes and a residue is left behind. (i) Name the salt. (ii) Write the equation for the decom-position reaction. Answer. (i) Lead nitrate is white salt. 28. When a solution of potassium iodide is added to a solution of lead nitrate in a test tube, a reaction takes place. (a) What type of reaction is this? (b) Write a balanced chemical equation to represent the above reaction. Answer. 29. Define combination reaction. Give one example of a combination reaction which is also exothermic. Answer. A reaction in which two elements or compounds combine to form a single compound is called combination reaction. It is also an exothermic reaction along with a combination reaction because heat is evolved. SHORT ANSWER TYPE QUESTIONS[II] [3 MARKS] 30. Classify the following reactions into different types. Prepared by: M. S. KumarSwamy, TGT(Maths) Page - 5 - (b) Which of the above reaction(s) is/are precipitation reaction(s)? Why is a reaction called precipitation reaction? Answer. (a) (i) Precipitation reaction (Double displacement reaction) (ii) Combination reaction (in) Decomposition reaction (b) Reaction (i) is a precipitation reaction because one of the product formed is insoluble in water. 31. Write balanced equations for the following mentioning the type of reaction involved. (i) Aluminium + Bromine —–> Aluminium bromide (ii) Calcium carbonate—–> Calcium oxide + Carbon dioxide (iii) Silver chloride—–>Silver + Chlorine Answer. 32. (a) Why is respiration considered as an exothermic reaction? (b) Define the terms oxidation and reduction. (c) Identify the substance that is oxidised and reduced in the following reaction. Answer. (a) It is because heat is evolved during respiration. (b) Oxidation is a process in which O2 is added or H2 is removed or loss of electrons take place. Reduction is a process in which H2 is added or O2 is removed or gain of electrons take place. (c) Zn is getting oxidised, CuO is getting reduced. 33. What is meant by (i) precipitation reaction, (ii) exothermic reaction, (iii) oxidation reaction? Write balanced chemical equations for an example of each. Answer.(i) Precipitation reaction: The reaction in which two compounds exchange their ions and the product formed is insoluble in water is called precipitation reaction. (ii) Exothermic reaction: The reaction in which heat is evolved is known as exothermic reaction. (iii) Oxidation reaction: The reaction in which O2 is added or H2 is removed or loss of electrons takes place is called oxidation reaction. 34. You might have noted that when copper powder is heated in a china dish, the surface of copper powder becomes coated with a black colour substance. (i) How has this black coloured substance formed? (ii) What is that black substance? (iii) Write the chemical equation of the reaction that takes place. Answer. (i) Copper reacts with oxygen to form copper oxide which is black, i.e. oxidation of copper takes place. (ii)Copper oxide Prepared by: M. S. KumarSwamy, TGT(Maths) Page - 6 - 35. “We need to balance a skeltal chemical equation.” Give reason to justify the statement. Answer. Skeltal chemical equation are unbalanced. We need to balance chemical equation because of law of conservation of mass. It states that ‘matter can neither be created nor be destroyed’. Therefore chemical equation must be balanced in each and every chemical reaction. 36. Giving an example list two information which make a chemical equation more useful (informative). Answer. (i) Physical state of reactants must be mentioned, e.g. 2H2 (g) + O2 (g)——–> 2H20 (l) (ii) Condition in which reaction takes place are written on the arrow head, e.g. 37. Consider the following chemical reaction X + Barium chloride——–> Y + Sodium chloride (White ppt) (a) Identify ‘X’ and ‘Y’ (b) The type of reaction Answer. (a) ‘X’ is Na2SO4 and Y is BaSO4. (b) The type of reaction Na2SO4 + BaCl2—–> BaSO4 + 2NaCl (White ppt) The reaction is precipitation reaction. It is also called double displacement reaction. 38. Name the reducing agent in the following reaction: 3MnO2 + 4Al———— > 3Mn + 2Al2O3 State which is more reactive, Mn or A1 and why? Answer. ‘Al’ is reducing agent. ‘Al’ is more reactive than Mn v ‘Al’ displaces Mn from its oxide. 39. (i) Write a balanced chemical equation for process of photosynthesis. (ii)When do desert plants take up carbon dioxide and perform photosynthesis? Answer. (ii) In desert plants the stomata are open at night. They take CO2 at night and is stored in the form of acid and is used during day time for photosynthesis. 40. What is observed when a solution of potassium iodide solution is added to a solution of lead nitrate? Name the type of reaction. Write a balanced chemical equation to represent the above chemical reaction. Answer. Yellow precipitate of lead iodide is formed. It is precipitation reaction. Pb( NO3)2 (aq) + 2KI (aq) —-> Pbl2 (s) + 2KNO3 (aq) It is also called double displacement reaction. 41. Write chemical equation reactions taking place when carried out with the help of (a) Iron reacts with steam (b) Magnesium reacts with dil HCl (c) Copper is heated in air. Answer. Prepared by: M. S. KumarSwamy, TGT(Maths) Page - 7 - 42. Write balanced chemical equations for the following reactions. (i) Silver bromide on exposure to sunlight decomposes into silver and bromine, (ii) Sodium metal reacts with water to form sodium hydroxide and hydrogen gas. Answer. 43. Identify the type of reaction(s) in the following equations. (i) CH4 + 2O2 ——–>CO2 + 2 H2O (ii) Pb(NO3)2 + 2KI ——–>Pbl2 + 2KNO3 (iii) CaO + H2O ——–> Ca(OH)2 (iv) CuSO4 + Zn ——–> ZnSO4 + Cu Answer. (i) Combustion reaction and oxidation reaction. (ii)Double displacement reaction and precipitation reaction. (iii) Combination reaction. (iv) Displacement reaction. 44. Write balanced equation for the reaction between magnesium and hydrochloric acid. Name the product obtained, identify the type of reaction. Answer. The product formed is magnesium chloride and hydrogen gas. It is a displacement reaction. 45. Describe an activity to observe what happens when quick lime is added to water taken in a beaker. State two important observations and name the type of reaction taking place. Answer. Aim: To observe what happens when quicklime is added to water taken in a beaker. Materials Required:- Quicklime (calcium oxide), water, beaker. Procedure: 1. Take 5 g of calcium oxide in a beaker. 2. Add water to it slowly. 3. Touch the beaker. 4. Note down the observations. Observation: Calcium oxide reacts with water vigorously to form calcium hydroxide with the evolution of heat. Chemical Reaction: Prepared by: M. S. KumarSwamy, TGT(Maths) Page - 8 - Conclusion: The reaction between CaO (Calcium oxide) and H2O is a combination reaction. It is an exothermic process because heat is evolved. 46. What is the colour of ferrous sulphate crystals? How does this colour change after heating? Answer. The colour of ferrous sulphate is pale green. The colour changes to reddish brown on heating due to formation of iron (III) oxide. Give an example each for thermal decomposition and photochemical decomposition reactions. Write relevant balanced chemical equations also. Thermal decomposition reaction: Photochemical decomposition reaction: 47. Why does the colour of copper sulphate solution change when an iron nail is dipped in it? Write two observations. Answer. It is because displacement reaction takes place. Iron displaces copper from copper sulphate solution and forms pale green coloured solution of FeS04 and reddish brown copper metal gets deposited. Fe(s) + CuS04(aq) ——–> FeS04(aq) + Cu(s) 48. Translate the following statement into chemical equation and then balance it Barium chloride reacts with aluminium sulphate to give aluminium chloride and a precipitate of barium sulphate. State the two types in which this reaction can be classified. Answer. 3BaCl2(aq) + A12(S04)3(aq) ——–> 3BaS04(s) + 2AlCl3(aq) It can be classified as double displacement as well as precipitation reaction. 49. Why are decomposition reactions called the opposite of combination reactions? Write equations for these reactions. Answer. In decomposition reaction, a compound is broken down into simpler compounds or elements, e.g. Combination reaction is a reaction in which two or more elements or compounds combine to form a new compound, e.g. Thus, decomposition and combination reactions are opposite to each other. 50. A Name the type of chemical reaction represented by the following equation: Answer. (i) Combination reaction (ii) Double displacement reaction (Precipitation reaction) (iii) Decomposition reaction. 51. Write the chemical equation of the reaction in which the following changes have taken place with an example of each: (i) Change in colour (ii) Change in temperature (iii) Formation of precipitate Answer. Prepared by: M. S. KumarSwamy, TGT(Maths) Page - 9 - (i)Cu (s) + 2AgNO3 (aq)———–> Cu(NO3)2(aq) + 2Ag The solution will become blue in colour and shiny silver metal will be deposited. (ii) NaOH + HCl ———–> NaCl + H2O+ heat The temperature will increase because heat will be evolved. (iii) Pb(NO3)2 (aq) + 2KI (aq)———–> Pbl2 (s) + 2KNO3 (aq) Yellow ppt Yellow precipitate of Pbl2 will be formed. 52. State the type of chemical reactions and chemical equations that take place in the following: (i) Magnesium wire is burnt in air. (ii) Electric current is passed through water. (iii) Ammonia and hydrogen chloride gases’are mixed. Answer. 53. (a) Write the essential condition for the following reaction to take place: 2AgBr—-> 2Ag + Br2 Write one application of this reaction. (b) Complete the following chemical equation of a chemical reaction (c) What happens when water is added to quick line. Write chemical equation. Answer. This reaction is used in photography. (c) Slaked lime is formed with hissing sound and lot of heat is envolved. 54. 2g of ferrous sulphate crystals are heated in a dry boiling tube. (i) List any two observations. (ii) Name the type of chemical reaction taking place. (iii) ‘Write the chemical equation for the reaction. Answer. (i) *Green colour of Fe SO4 disappears and reddish brown solid is formed. *Smell of burning sulphur. (ii) Decomposition reaction 55. Which products will be obtained when lead nitrate is heated simply. Write balanced chemical equation for the reaction? State the type of chemical reaction that occur in the change. Answer. Lead monoxide, nitrogen dioxide and oxygen gas will be liberated. It is thermal decomposition reaction. Prepared by: M. S. KumarSwamy, TGT(Maths) Page - 10 - 56. What is meant by skeltal type chemical equation? What does it represent? Using the equation for electrolytic decomposition of water, differentiate between a skeltal chemical equation and a balanced chemical equation. Answer. The equations in which gaseous are written in atomic form instead of molecular form and equation is not balanced, are called skeltal type equation. They represent gaseous elements formed in atomic state and equation is not balanced 57. The following diagram displays a chemical reaction. Observe carefully and answer the following questions (a) Identify the type of chemical reaction that will take place and define it. How will the colour of the salt change? Write the chemical equation of the reaction that takes place. (c) Mention one commercial use of this salt. Answer. (a) Photochemical decomposition reaction: Those reactions in which a compound breaks down into simple substances in presence of light are called photochemical decomposition reaction. The colour of salt will change from white to grey. (c) Silver chloride is used in photography. 58. What is rancidity? Mention any two ways by which rancidity can be prevented. Answer. The process in which taste and smell of food gets spoiled is called rancidity. It happens due to oxidation. Prevention from rancidity: (i) Antioxidants are added to fatty acids to prevent oxidation, e.g. chips are packed in presence of nitrogen gas which prevents spoilage by oxidation. (ii)Food should be kept in airtight container in refrigerator. 59. Write balanced chemical equation for the reactions that take place during respiration. Identify the type of combination reaction that takes place during this process and justify the name. Give one more example of this type of reaction. Answer. C6H1206 + 6O2 —————> 6CO2 + 6H20 + heat It is an exothermic combination reaction because heat is evolved. CH4(g) + 2O2(g) ————–>CO2 (g) + 2H20 Combustion of methane is another example of exothermic combination reaction. 60. What is redox reaction? Identify the substance oxidised and the substance reduced in the following reactions. (i)2PbO + C —–> 2Pb + CO2 (ii)MnO2 + 4HCl —–> MnCl2 + 2H20 + Cl2 Prepared by: M. S. KumarSwamy, TGT(Maths) Page - 11 - Answer. Those reactions in which oxidation and reduction takes place simultaneously are called redox reactions. (i) PbO is getting reduced and C is getting oxidised. (ii) MnOs is getting reduced and HCl is getting oxidised. 61. Write the balanced chemical equations for the following reactions and identify the type of reaction in each case. Thermite reaction, iron (III) oxide reacts with aluminium and gives molten iron and aluminium oxide. Answer. It is a displacement reaction because A1 is displacing Fe from Fe2O3. Molten iron is used’for repairing broken railway tracks. 62. A solution of potassium chloride when mixed with silver nitrate solution, an insoluble white substance is formed. Write the chemical reaction involved and also mention the type of the chemical reaction? Answer. It is a double displacement reaction. It is also a precipitation reaction as AgCl is a white precipitate. LONG ANSWER TYPE QUESTIONS [5 MARKS] 63. (a) Define a balanced chemical equation. Why should an equation be balanced? (b) Write the balanced chemical equation for the following reaction: (i) Phosphorus burns in presence of chlorine to form phosphorus penta chloride. (ii) Burning of natural gas. (iii) The process of respiration. Answer. (a) Balanced chemical equation has an equal number of atoms of different elements in the reactants and products. According to law of conservation of mass, matter can neither be created nor be destroyed in a chemical reaction. (b)(i) P4 (s) + 10Cl2 (g) ———> 4PCl5 (S) (i)CH4 (g) + 2O2 (g) ———> CO2 (g) + 2H2O(l) + heat energy (iii) C6H12O6 (s) + 6O2 (g) + 6H2O ———> 6CO2 (aq) + 12H2O (l) + energy 64. (a) Explain two ways by which food industries prevent rancidity. (b) Discuss the importance of decomposition reaction in metal industry with three points. Answer. (a) (i) Rancidity can be prevented by adding antioxidants to food containing fat and oil, e.g. butylated hydroxy anisole is added to butter as antioxidant. (ii) It can be prevented by packaging fat and oil containing foods in nitrogen gas. (b) (i) Molten NaCl is electrolytically decomposed to form sodium metal. (ii) Aluminium metal is obtained by electric decomposition of bauxite ore mixed with cryolite. (iii) Carbonate ores are thermally decomposed to give metal oxide which on reduction give metal. Prepared by: M. S. KumarSwamy, TGT(Maths) Page - 12 - 65. A metal nitrate ‘A’ on heating gives yellowish brown coloured metal oxide along with brown gas ‘B’ and a colourless gas ‘C’. Aqueous solution of ‘A’ on reaction with potassium iodide forms a yellow precipitate of compound ‘D’. Identify ‘A, B, C, D’. Also identify the types of both the reactions. Metal present in ‘A’ is used in alloy which is used for soldering purposes. Answer. Metal nitrate ‘A’ is Pb(NO3)2. ‘A’ is lead nitrate, ‘B’ is nitrogen dioxide, ‘C’ is oxygen and ‘D’ is lead iodide. (i) is decomposition reaction and (ii) is double displacement reaction (Precipitation reaction) 66. (a) Write one example for each of decomposion reaction carried out with help of (i) Electricity (ii) Heat (iii) Light (b) Which of the following statements is correct and why copper can displace silver from silver nitrate and silver can displace copper from copper sulphate solution. Answer. MULTIPLE CHOICE QUESTIONS [1 Mark] 1. 2 PbO(s) + C (s) → 2Pb(s) + CO2 (g) Which of the following statements are correct for the above? a) Lead is reduced. b) Carbon dioxide is oxidized. c) Carbon is oxidized. d) Lead oxide is reduced. i) (a)and (b) ii) (a) and (c) iii) (a), (b), and (c) d) all. 2. Balance the following chemical equations including the physical states. a) C6H12O6 → C2H5OH + CO2 b) Fe + O2 → Fe2O3 c) NH3 + Cl2 → N2H4+NH4Cl d) Na + H2O → NaOH +H2 3. Balance the chemical equation by including the physical states of the substances for the following reactions. a) Barium chloride and sodium sulphate aqueous solutions react to give insoluble Barium sulphate and aqueous solution of sodium chloride. b) Sodium hydroxide reacts with hydrochloric acid to produce sodium chloride and water. Prepared by: M. S. KumarSwamy, TGT(Maths) Page - 13 - c) Zinc pieces react with dilute hydrochloric acid to liberate hydrogen gas and forms zinc chloride 4. Which of the following is not a physical change? (a) Boiling of water to give water vapour (b) Melting of ice to give water (c) Dissolution of salt in water (d) Combustion of Liquefied Petroleum Gas (LPG) 5. The following reaction is an example of a 4NH3(g) + 5O2(g) → 4NO(g) + 6H2O(g) (i) displacement reaction (ii) combination reaction (iii) redox reaction (iv) neutralisation reaction (a) (i) and (iv) (b) (ii) and (iii) (c) (i) and (iii) (d) (iii) and (iv) 6. Which of the following statements about the given reaction are correct? 3Fe(s) + 4H2O(g) → Fe3O4(s) + 4H2(g) (i) Iron metal is getting oxidised (ii) Water is getting reduced (iii) Water is acting as reducing agent (iv) Water is acting as oxidising agent (a) (i), (ii) and (iii) (b) (iii) and (iv) (c) (i), (ii) and (iv) (d) (ii) and (iv) 7. Which of the following are exothermic processes? (i) Reaction of water with quick lime (ii) Dilution of an acid (iii) Evaporation of water (iv) Sublimation of camphor (crystals) (a) (i) and (ii) (b) (ii) and (iii) (c) (i) and (iv) (d) (iii) and (iv) 8. Three beakers labelled as A, B and C each containing 25 mL of water were taken. A small amount of NaOH, anhydrous CuSO4 and NaCl were added to the beakers A, B and C respectively. It was observed that there was an increase in the temperature of the solutions contained in beakers A and B, whereas in case of beaker C, the temperature of the solution falls. Which one of the following statement(s) is(are) correct? (i) In beakers A and B, exothermic process has occurred. (ii) In beakers A and B, endothermic process has occurred. (iii) In beaker C exothermic process has occurred. (iv) In beaker C endothermic process has occurred. (a) (i) only (b) (ii) only (c) (i) and (iv) (d) (ii) and (iii) 9. A dilute ferrous sulphate solution was gradually added to the beaker containing acidified permanganate solution. The light purple colour of the solution fades and finally disappears. Which of the following is the correct explanation for the observation? Prepared by: M. S. KumarSwamy, TGT(Maths) Page - 14 - (a) KMnO4 is an oxidising agent, it oxidises FeSO4 (b) FeSO4 acts as an oxidising agent and oxidises KMnO4 (c) The colour disappears due to dilution; no reaction is involved (d) KMnO4 is an unstable compound and decomposes in presence of FeSO4 to a colourless compound. 10. Which among the following is(are) double displacement reaction(s)? (i) Pb + CuCl2 → PbCl2 + Cu (ii) Na2SO4 + BaCl2 → BaSO4 + 2NaCl (iii) C + O2 → CO2 (iv) CH4 + 2O2 → CO2 + 2H2O (a) (i) and (iv) (b) (ii) only (c) (i) and (ii) (d) (iii) and (iv) 11. Which among the following statement(s) is(are) true? Exposure of silver chloride to sunlight for a long duration turns grey due to (i) the formation of silver by decomposition of silver chloride (ii) sublimation of silver chloride (iii) decomposition of chlorine gas from silver chloride (iv) oxidation of silver chloride (a) (i) only (b) (i) and (iii) (c) (ii) and (iii) (d) (iv) only 12. Solid calcium oxide reacts vigorously with water to form calcium hydroxide accompanied by liberation of heat. This process is called slaking of lime. Calcium hydroxide dissolves in water to form its solution called lime water. Which among the following is (are) true about slaking of lime and the solution formed? (i) It is an endothermic reaction (ii) It is an exothermic reaction (iii) The pH of the resulting solution will be more than seven (iv) The pH of the resulting solution will be less than seven (a) (i) and (ii) (b) (ii) and (iii) (c) (i) and (iv) (d) (iii) and (iv) 13. Barium chloride on reacting with ammonium sulphate forms barium sulphate and ammonium chloride. Which of the following correctly represents the type of the reaction involved? (i) Displacement reaction (ii) Precipitation reaction (iii) Combination reaction (iv) Double displacement reaction (a) (i) only (b) (ii) only (c) (iv) only (d) (ii) and (iv) Prepared by: M. S. KumarSwamy, TGT(Maths) Page - 15 - 14. Electrolysis of water is a decomposition reaction. The mole ratio of hydrogen and oxygen gases liberated during electrolysis of water is (a) 1:1 (b) 2:1 (c) 4:1 (d) 1:2 15. Which of the following is(are) an endothermic process(es)? (i) Dilution of sulphuric acid (ii) Sublimation of dry ice (iii) Condensation of water vapours (iv) Evaporation of water (a) (i) and (iii) (b) (ii) only (c) (iii) only (d) (ii) and (iv) 16. In the double displacement reaction between aqueous potassium iodide and aqueous lead nitrate, a yellow precipitate of lead iodide is formed. While performing the activity if lead nitrate is not available, which of the following can be used in place of lead nitrate? (a) Lead sulphate (insoluble) (b) Lead acetate (c) Ammonium nitrate (d) Potassium sulphate 17. Which of the following gases can be used for storage of fresh sample of an oil for a long time? (a) Carbon dioxide or oxygen (b) Nitrogen or oxygen (c) Carbon dioxide or helium (d) Helium or nitrogen 18. The following reaction is used for the preparation of oxygen gas in the laboratory Which of the following statement(s) is(are) correct about the reaction? (a) It is a decomposition reaction and endothermic in nature (b) It is a combination reaction (c) It is a decomposition reaction and accompanied by release of heat (d) It is a photochemical decomposition reaction and exothermic in nature 19. Which one of the following processes involve chemical reactions? (a) Storing of oxygen gas under pressure in a gas cylinder (b) Liquefaction of air (c) Keeping petrol in a china dish in the open (d) Heating copper wire in presence of air at high temperature 20. In which of the following chemical equations, the abbreviations represent the correct states of the reactants and products involved at reaction temperature? (a) 2H2(l) + O2(l) → 2H2O(g) (b) 2H2(g) + O2(l) → 2H2O(l) (c) 2H2(g) + O2(g) → 2H2O(l) (d) 2H2(g) + O2(g) → 2H2O(g) Prepared by: M. S. KumarSwamy, TGT(Maths) Page - 16 - 21. Which of the following are combination reactions? (a) (i) and (iii) (b) (iii) and (iv) (c) (ii) and (iv) (d) (ii) and (iii) 22. The removal of oxygen from a substance is called : (a) oxidation (b) corrosion (c) reduction (d) rancidity 23. In the context of redox reactions, the removal of hydrogen from a substance is known as : (a) oxidation (b) dehydration (c) reduction (d) dehydrogenation 24. The chemical reaction involved in the corrosion of iron metal is that of : (a) oxidation as well as displacement (b) reduction as well as combination (c) oxidation as well as combination (d) reduction as well as displacement 25. Give the characteristic tests for the following gases (a) CO2 (b) SO2 (c) O2 (d) H2 Prepared by: M. S. KumarSwamy, TGT(Maths) Page - 17 - METALS AND NON-METALS VERY SHORT ANSWER TYPE QUESTIONS [1 MARK] 1. A green layer is gradually formed on a copper plate left exposed to air for a week in a bathroom. What could this green substance be? Answer. It is due to the formation of basic copper carbonate [CuC03.Cu(0H)2]. 2. A non-metal X exists in two different forms Y and Z. Y is the hardest natural substance, whereas Z is a good conductor of electricity. Identify X, Y and Z. Answer. ‘X’ is carbon, ‘Y’ is diamond as it is the hardest natural substance and ‘Z’ is graphite as it is good conductor of electricity. 3. Metals generally occur in solid state. Name and write symbol of a metal that exists in liquid state at room temperature. Answer. Mercury(Hg) exists in liquid state at room temperature. 4. Which of the following two metals will melt at body temperature (37 °C) ? Gallium, Magnesium, Caesium, Aluminium Answer. Gallium and Caesium 5. From amongst the metals sodium, calcium, aluminium, copper and magnesium, name the metal (a) which reacts with water only on boiling, and (b) another which does not react even with steam. Answer. (a) Magnesium reacts with water only on boiling. (b) Copper does not react even with steam. 6. Which one of the following metals does not react with oxygen even at high temperatures ? (a) Calcium (b) Gold (c) Sodium Answer. (b) Gold does not react with oxygen even at high temperatures. 7. Name any one metal which reacts neither with cold water nor with hot water, but reacts with heated steam to produce hydrogen gas. Answer. Iron; 3Fe(s) + 4H2O(g) → Fe3O4(s) + 4H2(g) 8. Why does calcium float in water? Answer. It is because hydrogen gas is formed which sticks to surface of calcium, therefore it floats. 9. Name a non-metal which is lustrous and a metal which is non-lustrous. Answer. Iodine is a non-metal which is lustrous, lead is a non-lustrous metal. 10. Which gas is liberated when a metal reacts with an acid? How will you test the presence of this gas? Answer. Hydrogen gas is formed. Bring a burning matchstick near to it, H2 will burn explosively with ‘pop’ sound. 11. Name the metal which reacts with a very dilute HNO3 to evolve hydrogen gas. Answer. Magnesium 12. Name two metals which are found in nature in the free state. Answer.(i) Gold (ii) Silver Prepared by: M. S. KumarSwamy, TGT(Maths) Page - 18 - 13. What is the valency of silicon with atomic number 14? Answer. Its valency is equal to 4. 14. What is the valency of phosphorus with atomic number 15? Answer. Phosphorus has valency 3. 15. What is the valency of an element with atomic number 35? Answer. Its valency is 1. 16. Arrange the following metals in the decreasing order of reactivity: Na, K, Cu, Ag. Answer. K > Na > Cu > Ag 17. An element forms an oxide, A2O3 which is acidic in nature. Identify A as a metal or non- metal. Answer. ‘A’ is non-metal as non-metallic oxides are acidic in nature. 18. A green layer is gradually formed on a copper plate left exposed to air for a week in a bathroom. What could this green substance be ? Answer. It is due to the formation of basic copper carbonate [CuCO3.Cu(OH)2]. SHORT ANSWER TYPE QUESTIONS[I] [2 MARKS] 19. Write one example of each of (i) a metal which is so soft that, it can be cut with knife and a non-metal which is the hardest sustance. (ii) a metal and a non-metal which exist as liquid at room temperature. Answer. (i) Sodium, carbon (diamond). (ii)Mercury is liquid metal, bromine is liquid non-metal. 20. Mention the names of the metals for the following: (i) Two metals which are alloyed with iron to make stainless steel. (ii) Two metals which are used to make jewellary. Answer. (i) Nickel and chromium. (ii) Gold and platinum. 21. Give reason for the following: (a) School bells are made up of metals. (b) Electric wires are made up of copper. Answer. (a) It is because metals are sonorous, i.e. they produce sound when struk with a hard substance. (b) It-is because copper is good conductor of electricity. 22. Name the following: (a) A metal, which is preserved in kerosene. (b) A lustrous coloured non-metal. (c) A metal, which can melt while kept on palm. (d) A metal, which is a poor conductor of heat. Answer. Prepared by: M. S. KumarSwamy, TGT(Maths) Page - 19 - (a) Sodium is preserved in kerosene. (b) Iodine is lustrous coloured non-metal. (c) Gallium. (d) Lead. 23. Explain why calcium metal after reacting with water starts floating on its * surface. Write the chemical equation for the reaction. Name one more metal that starts floating after some time when immersed in water. Answer. Calcium starts floating because the bubbles of hydrogen gas formed stick to the surface of metal. Magnesium reacts with hot water and starts floating due to the bubbles of hydrogen gas sticking to its surface. 24. Give reason for the following: (a) Aluminium oxide is considered as an amphoteric oxide. (b) Ionic compounds conduct electricity in molten state. Answer. (a) It is because it reacts with acids as well as bases to produce salts and water.’Al’ is less electropositive metal. So, it forms amphoteric oxide which can react with acid as well as base. (b) Ionic compounds can conduct electricity in molten state because ions ’ become free to move in molten state. 25. Write two differences between calcination and roasting. Answer. 26. The way, metals like sodium, magnesium and iron react with air and water is an indication of their relative positions in the ‘reactivity series’. Is this statement true ? Justify your answer with examples. Answer.Yes, sodium reacts explosively even with cold water, it is most reactive. Magnesium reacts with hot water, it is less reactive than Na. Iron reacts only with steam which shows it is least reactive among the three. 27. X + YSO4——-> XSO4+ Y Y + XSO4 ——–> No reaction Out of the two elements, ‘X’ and ‘Y’, which is more reactive and why? Answer. ‘X’ is more reactive than ‘Y’ because it displaces ‘Y’ from its salt solution. 28. What is an alloy? State the constituents of solder. Which property of solder makes it suitable for welding electrical wires? Answer. Alloy is a homogeneous mixture of two or more metals. One of them can be a non-metal also. Solder consists of lead and tin. It has low melting point which makes it suitable for welding electrical wires. 29. When a metal X is treated with cold water, it gives a base Y with molecular formula XOH (Molecular mass = 40) and liberates a gas Z which easily catches fire. Identify X, Y and Z. Prepared by: M. S. KumarSwamy, TGT(Maths) Page - 20 - Answer. 30. Using the electronic configurations, explain how magnesium atom combines with oxygen atom to form magnesium oxide by transfer of electrons. Answer. 31. (a) Give two methods to prevent the rusting of iron. (b) Name the ores of the following metals: (i) mercury, and (ii) zinc Answer. (a)(i) Painting (ii) Galvanisation (b)(i) Cinnabar (ii) Zinc Blende 32. Write chemical equations that shows aluminium oxide reacts with acid as well as base. Answer. 33. Elements magnesium and oxygen respectively belong to group 2 and group 16 of the Modern Periodic Table. If the atomic numbers of magnesium and oxygen are 12 and 8 respectively, draw their electronic configurations and show the process of formation of their compound by transfer of electrons. Answer. Prepared by: M. S. KumarSwamy, TGT(Maths) Page - 21 - Mg(12)=2,8,2 SHORT ANSWER TYPE QUESTIONS[II] [3 MARKS] 34. State three reasons for the following facts (i) Sulphur is a non-metal (ii)Magnesium is a metal One of the reasons must be supported with a chemical equation. Answer. Sulphur is a non-metal Magnesium is a metal (i) Poor conductor of heat and electricity (i) Good conductor of heat and electricity (ii) Neither malleable nor ductile (ii) Malleable nor ductile (iii) S + O2 →SO2 (iii) 2Mg + O2 →2MgO2 SO2 + H2O → H2SO3 MgO + H2O → Mg(OH)2 (Sulphurous acid) (Magnesium hydroxide) Sulphur dioxide is acidic oxide. Magnesium oxide is basic in nature. 35. What is cinnabar? How is metal extracted from cinnabar? Explain briefly. Answer. Cinnabar is HgS. Mercury is obtained by roasting cinnabar. HgO formed is thermally unstable and gives mercury. Mercury can be purified by distillation. 36. (a) Write the electron dot structures for potassium and chlorine. (b) Show the formation of KCl by the transfer of electrons. (c) Name the ions present in the compound, KCl. Prepared by: M. S. KumarSwamy, TGT(Maths) Page - 22 - Answer. 37. (a)State the electron-dot structure for calcium and sulphur. (b) Show the formation of CaS by the transfer of electrons. (c) Name the ions present in this compound CaS. Atomic number of Ca = 20, O = 16. Answer. 38. You are given samples of three metals. Sodium, magnesium and copper. Suggest any two activities to arrange them in order of decreasing activity. Answer. Activity 1: Sodium reacts with cold water vigorously to form sodium hydroxide and hydrogen gas Magnesium does not react with cold water but with hot water to form magnesium ! hydroxide and hydrogen gas. Hence sodium is more reactive than magnesium. 39. You are provided with magnesium ribbon and sulpher powder. Explain with the help of an activity that metal oxides are basic and non-metal oxide are acidic in nature. Answer. Aim: To test the nature of oxides formed by metals and non-metals. Materials Required: Sulphur powder, Mg ribbon, water, blue litmus paper, red litmus paper. Procedure: 1.Take magnesium ribbon with a pair of tongs and burn it in flame in the presence of air. 2.Collect the product formed and dissolve it in warm water. 3.Add red litmus paper into it. 4.Observe the change in colour and decide the nature of the oxide formed. 5.Burn sulphur in a deflagrating spoon in the presence of air and dissolve the oxide formed in water. 6.Dip blue litmus paper into the solution and observe the changein the colour and decide the nature of the oxide formed. Prepared by: M. S. KumarSwamy, TGT(Maths) Page - 23 - Observation: The oxide formed by metal turns red litmus blue whereas oxide of non-metal turns blue litmus red. Chemical Reaction: Conclusion: Most of the metallic oxides are basic in nature whereas most of the non-metallic oxides are acidic in nature. 40. (a) Explain the formation of ionic compound CaO with electron dot structure. Atomic number of calcium and oxygen are 20 and 8 respectively. (b) Name the constituent metals of bronze. Answer. 41. A metal ‘X’ acquires a green colour coating on its surface on exposure to air. (i) Identify the metal ‘X’ and name the process responsible for this change. (ii)Name and write chemical formula of the green coating formed on the metal. (iii) List two important methods to prevent the process. Answer. (i) Metal is copper. The process is corrosion. (ii)Basic copper carbonate [CuCO3.Cu(0H)2]. (iii) It should be coated with tin It should be mixed with other metals to form alloys 42. Write balanced equations for the reaction of: (i) aluminium when heated in air. Write the name of the product. (ii) iron with steam. Name the product obtained. (iii) calcium with water. Why does calcium start floating in water? Answer. Prepared by: M. S. KumarSwamy, TGT(Maths) Page - 24 - 43. Write balanced chemical equations for the following reactions: (a) Dilute sulphuric acid reacts with aluminium powder. (b) Dilute hydrochloric acid reacts with sodium carbonate. (c) Carbon dioxide is passed through lime water. Answer. 44. (a) Show the formation of Na2O by the transfer of electrons between the combining atoms. (b) Why are ionic compounds usually hard? (c) How is it that ionic compounds in the solid state do not conduct electricity but they do so when in molten state? Answer. (b) It is due to strong force of attraction between oppositely charged ions. (c) In solid state, ions are not free to move whereas in molten state ions are free to move, therefore, they conduct electricity in molten state. 45. (a) Show on a diagram the transfer of electrons between the atoms in the formation of MgO. Write symbols of cation and anion present in MgO. (b) Name the solvent in which ionic compounds are generally soluble. (c) Why are aqueous solutions of ionic compounds able to conduct electricity? Answer. (b) Ionic compounds are soluble in water. (c) It is because aqueous solutions consist of ions which can move freely in them and carry current. 46. What are amphoteric oxides? Choose the amphoteric oxides from amongst the following oxides: Na2O, ZnO, Al2O3, CO2, H2O Answer.Those oxides which reacts with acids as well as bases to produce salts and water are called amphoteric oxides, e.g. Na2O, ZnO, are amphoteric oxides among given oxides. 47. An ore on heating in air produces sulphur dioxide. Which process would you suggest for its concentration? Describe briefly any two steps involved in the conversion of this concentrated ore into related metal. Answer. It is concentrated by froth-floatation process. Prepared by: M. S. KumarSwamy, TGT(Maths) Page - 25 - (i) Roasting: The concentrated sulphide ore is heated strongly in the presence of oxygen to convert it into its oxide. (ii)Reduction : This oxide of metal is reduced with suitable reducing agent to get free metal. 48. Give reasons for the following observations: (i) Ionic compounds in general have high melting and boiling points. (ii) Highly reactive metals cannot be obtained from their oxides by heating them with carbon. (iii) Copper vessels get a green coat when left exposed to air in the rainy season. Answer. (i) Ionic compounds have high melting and boiling points due to strong force of attraction between oppositely charged ions. (ii) It is because these metals themselves are strong reducing agents. Therefore, cannot be reduced by reducing agent like carbon. (iii) Copper vessels react with CO2, O2 and moisture to form green-coloured basic copper carbonate [CuCO3.Cu(OH)2]. 49. State reasons for the following observations: (i) The shining surface of some metals becomes dull when exposed to air for a long time. (ii) Zinc fails to evolve hydrogen gas on reacting with dilute nitric acid. (iii) Metal sulphides occur mainly in rocks but metal halides occur mostly in sea and lake waters. Answer. (i) It is because metal reacts with substances present in atmosphere to form surface compounds which make it dull. (ii) It is because dil. HNO3 is an oxidising agent therefore zinc gives NO and not H2 with dil. HNO3. (iii) It is because sea water contains sodium chloride due to which metal halides are formed, whereas sulphur is found below rocks. Therefore, metal – sulphides are formed in rocks. 50. State reasons for the following: (i) Electric wires are covered with rubber like material. (ii)From dilute hydrochloric acid, zinc can liberate hydrogen gas but copper cannot. (iii) Sulphide ore of a metal is first converted to its oxide to extract the metal from it. Answer. (i) It is because rubber is an insulator and does not allow current to flow through it. (ii) Zinc is more reactive than hydrogen. Therefore, it can displace hydrogen from dilute HCl whereas copper cannot, because it is less reactive than hydrogen. , (iii) It is because it is easier to reduce oxide ore as compared to sulphide ore. Long Answer Type Question [5 Marks] 51. (a) Write electron dot diagram for chlorine (At No. 17) and calcium (At No. 20). Show the formation of calcium chloride by transfer of electrons. (b) Identify the nature of above compound’and explain three physical properties of such compound. Answer. Prepared by: M. S. KumarSwamy, TGT(Maths) Page - 26 - (b) It is ionic compound. Physical properties 1.It is hard and solid. 2.It has high melting and boiling point. 3.It soluble in water. 52. (a) Define activity series of metals. Arrange the metals gold, copper, iron and magnesium in order of their increase in reactivity. (b) What will you observe when: (i) Some zinc pieces are put in copper sulphate solution. (ii) Some silver pieces are put into green coloured ferrous sulphate solution. Answer. (a) The series of metals in which metals are arranged in decreasing order of their reactivity. Au < Cu < Fe < Mg is increasing order of reactivity. (b) (i) The blue solution will become colourless and reddish brown copper metal will be deposited. Reaction will not take place because Ag’ is less reactive than iron. 53. (a) In the formation of compound between two atoms A and B, A loses two electrons and B gains one electron. (i) What is the nature of bond between A and B? (ii) Suggest the formula of the compound formed between A and B. (b) On similar lines explain the formation of MgCl2 molecule. (c) Common salt conducts electricity only in the molten state. Why? (d) Why is melting point of NaCl high? Answer. 54. Write the names and symbols of two most reactive metals. Explain by drawing electronic structure how any one of the two metals react with a halogen. State any four physical properties of the compound formed. Answer. K(Potassium) and Na(Sodium) are the two most reactive metals. K’ and Na‘ are electronic structures as they have one valence electron. Prepared by: M. S. KumarSwamy, TGT(Maths) Page - 27 - where ‘F’ is a halogen. Four physical properties of the compounds formed by these elements and halogens are: (i) They have high melting point. (ii)They are soluble in water. (iii) They conduct electricity in molten state not in solid state. (iv) They are solid and somewhat hard. 55. Give reasons for the following: (i) Silver and copper lose their shine when they are exposed to air. Name the substance formed on their surface in each case. (ii) Tarnished copper vessels are cleaned with tamarind juice. (iii) Aluminium is more reactive than iron yet there is less corrosion of aluminium as compared to iron when both are exposed to air. Answer. (i) These metals get corroded. Silver forms black Ag2S (silver sulphide) and copper form greenish layer of basic copper carbonate CuCO3. Cu(OH)2. (ii) Tamarind contains acid which reacts with basic copper carbonate and product gets dissolved and removed from copper vessel. (in) Aluminium forms oxide layer on its surface which does not further react with air. 56. (a) Write the electron dot structures of sodium, oxygen and magnesium. (b) Show the formation of Na2O and MgO by transfer of electrons. Name the ions present in these compound. (c) List three properties of ionic compounds. Answer. (i) They are solids having high melting point. (ii) They are soluble in water. (iii) They conduct electricity in molten state as well as in aqueous solution. 57. A metal (E) is stored under kerosene. When a small piece of it is left open in the air, it catches fire. When the product formed is dissolved in water, it turns red litmus to blue. (i) Name the metal (E). (ii)Write the chemical equation for the reaction when it is exposed to air and when the product is dissolved in water. (iii) Explain the process by which the metal is obtained from its molten chloride. Answer. Prepared by: M. S. KumarSwamy, TGT(Maths) Page - 28 - (i) ‘E’ is sodium which catches fire in presence of moisture. (iii) Electrolytic reduction: Electric current is passed through molten NaCl. Sodium is formed at cathode and chlorine gas is liberated at anode. 58. (a) How can the metals at the top of the reactivity series be extracted from their ores? Explain with an example. (b) Name any one alloy made from (i) a metal and a non-metal, and (ii) two metals. Answer. (a) These metals are extracted by electrolytic reduction, e.g. aluminium is obtained from bauxite by electrolytic reduction. (b) (i) Steel is made up of iron and carbon. (ii) Brass is made up of copper and zinc. 59. With the help of a suitable example, explain how ionic compounds are formed. State any three general properties of ionic compounds. Answer.Ionic compounds are formed by transfer of electrons from metal to non-metals, e.g. General Properties: (i) They are the solids having high melting point. (ii) They are soluble in water. (iii) They conduct electricity in molten state as well as in aqueous solution. 60. (a) Explain with an example how the metal (X) which is low in reactivity series and metal (Y) which is high in the reactivity series are obtained from their compounds by reduction process. (b) Write the electronic configurations of sodium and chlorine. Show the formation of sodium chloride from sodium and chlorine by the transfer of electrons. (c) List any two observations when a highly reactive metal is dropped in water. Answer. (a) ‘X’ is obtained by chemical reduction. ‘Y’ is obtained by electrolytic reduction. (c) (i) Metal will catch fire. (ii) Alkali solution is formed which turns red litmus blue. 61. (a) The reaction of metal (X) with ferric oxide is highly exothermic. Metal (X) is obtained from its oxides by electrolytic reduction. Identify (X) and write its reaction with ferric oxide. Prepared by: M. S. KumarSwamy, TGT(Maths) Page - 29 - (b) Give reason to justify that aluminium oxide is an amphoteric oxide. Also, give another example of amphoteric oxide. (c) Mention constituent metals present in bronze. Answer. (a) ‘X’ is ‘Al’ (b) AI2O3 reacts with acid as well as base therefore it is amphoteric oxide. Zinc oxide is also an amphoteric oxide. (c) Bronze contains’ copper and tin. 62. No reaction takes place when granules of a solid ‘A’ are mixed with a powder of solid ‘B\ However when the mixture is heated, a reaction starts with evolution of much heat. Product ‘C’ of the reaction settles down as a liquid metal and solid product ‘D’ keeps floating over the liquid ‘C\ This reaction is sometimes used for making metals for ready use in odd places. (i) Based on this information, make assumptions about ‘A’ and ‘B’ and corresponding deductions about ‘C’ and ‘D’ and write a balanced chemical equation for the reaction. Include in the chemical equation about physical states of the reactants and products, need of heating for starting the reaction and the reaction being exothermic. (ii) Name two types of chemical reactions to which this reaction can belong. Answer. (i) ‘A’ is aluminum, ‘B’ is ferric oxide [Iron(III) oxide], (ii)This reaction is displacement reaction because AT is displacing ‘Fe’. It is also a redox reaction because AT is reducing agent and Fe2O3is oxidising agent. 63. (a) Distinguish between ionic and covalent compounds under the following properties: (i) Strength of forces between constituent elements. (ii) Solubility of compounds in water. (iii) Electrical conduction in substances. (b) Explain how the following metals are obtained from their compounds by the reduction process: (i) Metal M which is in the middle of the reactivity series. (ii) Metal N which is high up in the reactivity series. Give one example of each type. Answer. Ionic Compounds Covalent Compounds (i) Strength – They have strong forces of They have weak forces of attraction. attraction (ii) Solubility – They are soluble in water They are insoluble in water (iii) Conduction – They conduct They do not conduct electricity in aqueous electricity in aqueous solution. solution. (b) (i) Metal M which is in the middle of the reactivity series is reduced by aluminium, e.g. 3MnO2(s) + 4Al(s) ——–> 2Al2O3(s) + 3Mn(l) (ii) Metal N will be obtained by electrolytic reduction, e.g. A1 is obtained by electrolytic reduction. OBJECTIVE TYPE QUESTIONS [1 MARK] Prepared by: M. S. KumarSwamy, TGT(Maths) Page - 30 - 1. Which of the following can be beaten into thin sheets? (a) Zinc (b) Phosphorus (c) Sulphur (d) Oxygen 2. Which of the following statements is correct? (a) All metals are ductile. (b) All non-metals are ductile. (c) Generally, metals are ductile. (d) Some non-metals are ductile. 3. Which of the following is not a metal? (a) copper (b) sulphur (c) aluminium (d) iron 4. The substance that will be flattened on beating with a hammer is (a) crystal of iodine (b) lump of sulphur (c) piece of coal (d) zinc granule 5. Arun has learnt that non-metals on beating with a hammer are generally broken into pieces. Which of the following is a nonmetal? (a) iron nail (b) aluminium wire (c) copper plate (d) piece of coal 6. Materials which can be drawn into wires are called ductile. Which of the following is not a ductile material? (a) silver (b) copper (c) sulphur (d) aluminium 7. Metals are generally hard. Which of the following metals is an exception and can be cut with a knife? (a) iron (b) sodium (c) gold (d) magnesium 8. Metals are generally solid. Which of the following metals is in the liquid state at room temperature? (a) mercury (b) silver (c) aluminium (d) sodium 9. Metals generally react with dilute acids to produce hydrogen gas. Which one of the following metals does not react with dilute hydrochloric acid? (a) magnesium (b) aluminium (c) iron (d) copper 10. Which of the following reacts with cold water vigorously? (a) carbon (b) sodium (c) magnesium (d) sulphur 11. The metal which produces hydrogen gas on reaction with dilute hydrochloric acid as well as sodium hydroxide solution is (a) copper (b) iron (c) aluminium (d) sodium 12. Which of the following non-metals reacts and catches fire on exposure to air? (a) phosphorus (b) nitrogen (c) sulphur (d) hydrogen 13. Generally metallic oxides are basic and non-metallic oxides are acidic in nature. Solution of which of the following oxides in water will change the colour of blue litmus to red? (a) sulphur dioxide (b) magnesium oxide (c) iron oxide (d) copper oxide 14. Which of the following property is not responsible for copper to be used as electrical conduction wires? (a) ductility (b) colour (c) good conductor of electricity (d) it is solid 15. The ability of metals to be drawn into thin wire is known as Prepared by: M. S. KumarSwamy, TGT(Maths) Page - 31 - (a) ductility (b) malleability (c) sonorousity (d) conductivity 16. Aluminium is used for making cooking utensils. Which of the following properties of aluminium are responsible for the same? (i) Good thermal conductivity (ii) Good electrical conductivity (iii) Ductility (iv) High melting point (a) (i) and (ii) (b) (i) and (iii) (c) (ii) and (iii) (d) (i) and (iv) 17. Which of the following property is generally not shown by metals? (a) Electrical conduction (b) Sonorous in nature (c) Dullness (d) Ductility 18. Which one of the following metals do not react with cold as well as hot water? (a) Na (b) Ca (c) Mg (d) Fe 19. Which of the following oxide(s) of iron would be obtained on prolonged reaction of iron with steam? (a) FeO (b) Fe2O3 (c) Fe3O4 (d) Fe2O3 and Fe3O4 20. What happens when calcium is treated with water? (i) It does not react with water (ii) It reacts violently with water (iii) It reacts less violently with water (iv) Bubbles of hydrogen gas formed stick to the surface of calcium (a) (i) and (iv) (b) (ii) and (iii) (c) (i) and (ii) (d) (iii) and (iv) 21. Generally metals react with acids to give salt and hydrogen gas. Which of the following acids does not give hydrogen gas on reacting with metals (except Mn and Mg)? (a) H2SO4 (b) HCl (c) HNO3 (d) All of these 22. Which of the following are not ionic compounds? (i) KCl (ii) HCl (iii) CCl4 (iv) NaCl (a) (i) and (ii) (b) (ii) and (iii) (c) (iii) and (iv) (d) (i) and (iii) 23. Which one of the following properties is not generally exhibited by ionic compounds? (a) Solubility in water (b) Electrical conductivity in solid state (c) High melting and boiling points (d) Electrical conductivity in molten state 24. Which of the following metals exist in their native state in nature? (i) Cu (ii) Au (iii) Zn (iv) Ag (a) (i) and (ii) (b) (ii) and (iii) (c) (ii) and (iv) (d) (iii) and (iv) 25. Silver articles become black on prolonged exposure to air. This is due to the formation of (a) Ag3N (b) Ag2O (c) Ag2S (d) Ag2S and Ag3N 26. Stainless steel is very useful material for our life. In stainless steel, iron is mixed with (a) Ni and Cr (b) Cu and Cr (c) Ni and Cu (d) Cu and Au Prepared by: M. S. KumarSwamy, TGT(Maths) Page - 32 - 27. If copper is kept open in air, it slowly loses its shining brown surface and gains a green coating. It is due to the formation of (a) CuSO4 (b) CuCO3 (c) Cu(NO3)2 (d) CuO 28. Generally, metals are solid in nature. Which one of the following metals is found in liquid state at room temperature? (a) Na (b) Fe (c) Cr (d) Hg 29. Which of the following metals are obtained by electrolysis of their chlorides in molten state ? (i) Na (ii) Ca (iii) Fe (iv) Cu (a) (i) and (iv) (b) (iii) and (iv) (c) (i) and (iii) (d) (i) and (ii) 30. Generally, non-metals are not lustrous. Which of the following nonmetal is lustrous? (a) Sulphur (b) Oxygen (c) Nitrogen (d) Iodine 31. Which one of the following four metals would be displaced from the solution of its salts by other three metals? (a) Mg (b) Ag (c) Zn (d) Cu 32. 2 mL each of concentrated HCl, HNO3 and a mixture of concentrated HCl and concentrated HNO3 in the ratio of 3 : 1 were taken in test tubes labelled as A, B and C. A small piece of metal was put in each test tube. No change occurred in test tubes A and B but the metal got dissolved in test tube C respectively. The metal could be (a) Al (b) Au (c) Cu (d) Pt 33. An alloy is (a) an element (b) a compound (c) a homogeneous mixture (d) a heterogeneous mixture 34. An electrolytic cell consists of (i) positively charged cathode (ii) negatively charged anode (iii) positively charged anode (iv) negatively charged cathode (a) (i) and (ii) (b) (iii) and (iv) (c) (i) and (iii) (d) (ii) ad (iv) 35. An element A is soft and can be cut with a knife. This is very reactive to air and cannot be kept open in air. It reacts vigorously with water. Identify the element from the following (a) Mg (b) Na (c) P (d) Ca 36. Which among the following statements is incorrect for magnesium metal? (a) It burns in oxygen with a dazzling white flame (b) It reacts with cold water to form magnesium oxide and evolves hydrogen gas (c) It reacts with hot water to form magnesium hydroxide and evolves hydrogen gas (d) It reacts with steam to form magnesium hydroxide and evolves hydrogen gas 37. Which among the following alloys contain mercury as one of its constituents? (a) Stainless steel (b) Alnico (c) Solder (d) Zinc amalgam 38. Reaction between X and Y, forms compound Z. X loses electron and Y gains electron. Which of the following properties is not shown by Z? (a) Has high melting point (b) Has low melting point (c) Conducts electricity in molten state (d) Occurs as solid Prepared by: M. S. KumarSwamy, TGT(Maths) Page - 33 - 39. The electronic configurations of three elements X, Y and Z are X — 2, 8; Y — 2, 8, 7 and Z — 2, 8, 2. Which of the following is correct? (a) X is a metal (b) Y is a metal (c) Z is a non-metal (d) Y is a non-metal and Z is a metal 40. Although metals form basic oxides, which of the following metals form an amphoteric oxide? (a) Na (b) Ca (c) Al (d) Cu 41. Generally, non-metals are not conductors of electricity. Which of the following is a good conductor of electricity? (a) Diamond (b) Graphite (c) Sulphur (d) Fullerene 42. Electrical wires have a coating of an insulting material. The material, generally used is (a) Sulphur (b) Graphite (c) PVC (d) All can be used 43. Which of the following non-metals is a liquid? (a) Carbon (b) Bromine (c) Phosphorus (d) Sulphur 44. Which of the following can undergo a chemical reaction? (a) MgSO4 + Fe (b) ZnSO4 + Fe (c) MgSO4 + Pb (d) CuSO4 + Fe Prepared by: M. S. KumarSwamy, TGT(Maths) Page - 34 - CARBON AND ITS COMPOUNDS VERY SHORT ANSWER TYPE QUESTION [1 Mark] 1. Give the names of the following functional groups: (i) —OH (ii) —COOH Answer. (i) Alcohol group (ii) Carboxylic acid group 2. What is the difference in the molecular formula of any two consecutive members of a homologous series of organic compounds? Answer. —CH2— is the difference in the molecular formula of any two consecutive members of a homologous series of organic compounds. 3. Name the carbon compound which on heating with excess of concentrated sulphuric acid at 443 K gives ethene. Answer. 4. What is meant by a saturated hydrocarbon? Answer. Those hydrocarbons in which valency of carbon is satisfied by single bonds only are called saturated hydrocarbons. 5. Name the compound formed when ethanol is warmed with ethanoic acid in the presence of a few drops of cone.H2S04 Answer. 6. Draw the structure of CH3COOH molecule. Answer. 7. Draw the structure of ethanol molecule. Answer. 8. What happens when a small piece of sodium is dropped into ethanol? Answer. 9. Carbon has four electrons in its valence shell. How does carbon attain stable electronic configuration. Answers. By sharing four electrons with other atoms. Prepared by: M. S. KumarSwamy, TGT(Maths) Page - 35 - 10. State two characteristic features of carbon which when put together give rise to large number of carbon compounds. Answer. (i) Catenation (ii) Tetravalency of carbon 11. Write the structural formula of chloroethane. Answer. 12. How many covalent bonds are there in a molecule of ethane (C2H6)? Answer. There are 7 covalent bonds in a molecule of ethane. 13. Write the electron dot structure of ethene molecule (C2H4). Answer. 14. Write the electron dot structure of ethane molecule (C2H6). Answer. 15. Draw the structure of butanone molecule, CH3COC2H5. Answer. 16. Draw the structure of the hexanal molecule, C5H11CHO. Answer. 17. Butanone is a four carbon per molecule compound. Name the functional group present in it. Answer. Ketone 18. Name the functional group present in each of the following organic compounds: (i) C2H5CI Prepared by: M. S. KumarSwamy, TGT(Maths) Page - 36 - (ii) C2H5OH Answer. (i) (—Cl) Halogen (Chloro) (ii) (—OH) Alcohol 19. Name the functional group present in each of the following compounds: (i) HCOOH (ii) C2H5CHO Answer. (i) —COOH (Carboxylic acid) (ii) —CHO (Aldehyde) 20. Name the functional group present in each of the following organic compounds: (i)CH3COCH3 (ii) C2H5COOH Answer. 21. Write the name and formula of the second member of the carbon compounds having functional group —OH. Answer. 22. Write the name and formula of the first member of the carbon compounds having functional group —CHO. Answer. 23. Write the name and formula of the first member of the carbon compounds having functional group —COOH. Answer. 24. Write the name and formula of the 2nd member of the series of carbon compounds whose general formula is CnH2n+1OH Answer. Ethanol, C2H5OH or CH3CH2OH 25. Write the name and formula of the 2nd member of the series of carbon compounds whose general formula is CnH2n. Answer. C3H6, H2C=CH—CH3 Propene is second member of series whose general formula is CnH2n. SHORT ANSWER TYPE QUESTIONS[I] [2 Marks] 26. (a) Give a chemical test to distinguish between saturated and unsaturated hydrocarbons. (b) (i) Name the products formed when ethanol burns in air. ‘ Prepared by: M. S. KumarSwamy, TGT(Maths) Page - 37 - (ii) What two forms of energy are liberated on burning alcohol? (c) Why is the reaction between methane and chlorine considered a substitution reaction? Answer. 27. (a) Why are covalent compounds generally poor conductors of electricity? (b) Name the following compound: (c) Name the gas evolved when ethanoic acid is added to sodium carbonate. How would you prove the presence of this gas? Answer. 28. Write the name and molecular formula of an organic compound having its name suffixed with ‘-ol and having two carbon atoms in the molecule. With the help of a balanced chemical equation indicate what happens when it is heated with excess of r cone.H2S04. Answer. 29. Explain why carbon generally forms compounds by covalent bonds. Answer. Carbon cannot lose four electrons easily because very high energy is required. It cannot gain four electrons easily because six protons cannot hold 10 electrons. It can easily share four electrons forming covalent bonds. 30. Write the names and molecular formula of two organic compounds having functional r group suffixed as ‘-oic acid’. With the help of a balanced chemical equation and explain what happens when any one of them reacts with sodium hydroxide. Prepared by: M. S. KumarSwamy, TGT(Maths) Page - 38 - Answer. 31. Atom of an element contains five electrons in its valence shell. This element is major component of air. It exists as a diatomic molecule. (i) Identify the element. (ii) Show the bond formed between two atoms of this element. (iii) Write the nature of the bond between the two atoms. Answer. (i) Nitrogen. (ii) (iii) Covalent bond. 32. What is a homologous series? Which two of the following organic compounds belong to the same homologous? CH3 ,C2H6, C2H6O, C2H6O2,CH4O Answer. Homologous series is a series of organic compounds which have same functional group and similar chemical properties. Each member of this series is differ by —CH2— in its molecular formula and 14 u in its molecular mass. C2H6O (C2H5OH) and CH4O (CH3OH) belong to same homologous series. SHORT ANSWER TYPE QUESTIONS[II] [3 Marks] 33. What is meant by a functional group in an organic compound? Name the functional group present in (i) CH3CH2OH (ii) CH3COOH Answer. Functional group is an atom or group of atoms or reactive part of compound, which determines chemical properties of compounds. (i) —OH (Alcohol) (ii) —COOH (Carboxylic acid) 34. Give reasons for the following observations: (a) The element carbon forms a very large number of compounds. (b) Air holes of a gas burner have to be adjusted when the heated vessels get blackened by the flame. Answer. (a) Carbon forms large number of compounds since carbon is small in size and can form stable covalent bonds (catenation) and it shows tetravalency. (b) Air holes of gas burner are made open (adjusted) so that air can pass through, which is needed for complete combustion, so that heated vessels do not get blackened. Prepared by: M. S. KumarSwamy, TGT(Maths) Page - 39 - 35. What are isomers? Draw the structures of two isomers of butane, C4H10. Why can’t we have isomers of first three members of alkane series? Answer. Those compounds, which have same molecular formula but different structural formulae are called isomers. In first three members of alkane series, branching is not possible. Therefore, we cannot have isomers. 36. An organic compound ‘A’ is an essential constituent of wine and beer. Oxidation of ‘A’ yields an organic acid ‘B’ which is present in vinegar. Name the compounds ‘A’ and ‘B’ and write their structural formula. What happens when ‘A’ and ‘B’ react in the presence of an acid catalyst? Write the chemical equation for the reaction. Answer. 37. Define homologous series of organic compounds. List its two characteristics. Write the name and formula of the first member of the series of alkenes. Answer. The series of organic compounds having same functional group and similar chemical properties is called homologous series. Each member differs from successive member by —CH2— group. The difference in molecular weight between two successive members is 14 u. Characteristics: (i) It has same general formula, from which, all members can be derived. (ii) They have similar chemical properties. C2H4, CH2=CH2, Ethene is first member of alkene series. 38. Why homologous series of carbon compounds are so called? Write chemical formula of two consecutive members of a homologous series and state the part of these compounds that determines their (i) physical properties, and (ii) chemical properties. Answer. The series consists of members of same family with similar physical and chemical properties, therefore, called homologous series (i) CH3OH, and (ii) CH3CH2OH are two consecutive members of homologous series. Alkyl group —CH3 and —CH3CH2 part determines physical properties. Functional group —OH determines chemical properties of the compounds. LONG ANSWER TYPE QUESTIONS [5 Marks] 39. (a) State two properties of carbon which lead to a very large number of carbon compounds. (b) Why does micelle formation take place when soap is added to water? Why are micelles not formed when soap is added to ethanol? Prepared by: M. S. KumarSwamy, TGT(Maths) Page - 40 - Answer. (a) (i)-Catenation (ii) Tetravalency (b) It is because large number of molecular ions of soaps get aggregated and form colloidal solution. Soap has hydrophobic tail (hydrocarbon) which dissolves in hydrocarbon part and hydrophilic part dissolves in water. Ethanol is non-polar solvent therefore micelles are not formed because hydrocarbon part gets attracted towards ethanol and ionic end will not dissolve in alcohol. 40. Explain isomerism. State any four characteristics of isomers. Draw the structures of possible isomers of butane, C4H10 Answer. Isomerism is a phenomenon due to which some compounds have same molecular formula but different structural formulae. Characteristics: (i) They differ in structural formula. (ii) They differ in melting point. (iii) They differ in boiling point. (iv) They differ in solubility in same solvent. 41. Give reasons for the following: (i)Element carbon forms compounds mainly by covalent bonding. (ii)Diamond has a high melting point. (iii)Graphite is a good conductor of electricity. (iv)Acetylene bums with a sooty flame. (v)Kerosene does not decolourise bromine water while cooking oils do. Answer. (i) It is because carbon has four valence electrons, it cannot gain or lose four electrons because high energy is needed. It can only share four electrons. (ii) It is due to strong covalent bonds and compact structure of diamond. (iii) It is due to presence of free electrons in graphite because each carbon is linked to three more carbon atoms. (iv) It is due to high percentage of carbon, it burns with sooty or smoky flame. (v) Kerosene oil is mixture of saturated hydrocarbons therefore does not decolourise bromine water. 42. What are the hydrocarbons? Write the name and general formula of (i) saturated hydrocarbons, (ii) unsaturated hydrocarbons, and draw the structure of one hydrocarbon of each type. How can an unsaturated hydrocarbon be made saturated? Prepared by: M. S. KumarSwamy, TGT(Maths) Page - 41 - Answer. MULTIPLE CHOICE QUESTIONS [1 Mark] 1. Which of the following is not a saturated hydrocarbon ? i) Cyclohexane. ii) Benzene. iii) Butane iv) isobutene 2. The bond between two identical non metallic atom has a pair of electron ? i) un equally shared between two atoms. ii) Transferred completely from one atom to another. iii) With identical spins iv) Unequally shared between them. 3. Covalent compounds are generally i) Soluble in water ii) Insoluble in water iii) Ionize in water iv) Hydrolyse in water 4. Propane with the molecular formula C3H8 has Prepared by: M. S. KumarSwamy, TGT(Maths) Page - 42 - i) 7covalent bonds ii) 8 covalent bonds iii) 9 covalent bonds iv) 10 Covalent bonds. 5. Which of the following is not an allotropic form of carbon i)fluorine ii)fullerene iii)diamond iv)graphite 6. Which of the following represents the correct decreasing order of hydrogen atoms ? i)alkanes , alkenes , alkynes ii)alkanes , alkaynes , alkenes iii)alkenes , alkynes , alkanes iv)alkynes , alkanes , alkenes 7. Which of the following represents the structure of N2 Mmolecule ? i) N≡ N ii) N = N iii) N - N iv) None of the above 8. In double covalent bond there is sharing of i) 2 electrons ii) 4 electrons iii) 6 electrons iv) 3 electrons 9. Cation is formed when i) atom gains electrons ii) atom loses electrons iii) proton is lost by the atom iv) atom shared by electrons 10. The total no. of electrons that take part in forming a bond in N2 is i) 2 ii) 4 iii) 6 iv) 10 11. Which of the following has the weakest carbon-carbon strength? i)C2H2 ii)C2H4 iii)C2H6 iv)all have the same bond strength 12. Which of the following salt when dissolved in water produce hard water. i) calcium sulphate ii) magnesium bicarbonate iii) calcium chloride iv) any of the above 13. Which of the following is not a saturated hydrocarbon ? Prepared by: M. S. KumarSwamy, TGT(Maths) Page - 43 - i) cyclohexane ii) benzene iii) butane iv) isobutene 14. The bond between two identical nonmetallic atom has a pair of electron ? i) unequally shared between two atoms ii) transferred completely from one atom to another iii) With identical spins iv) Equally shared between them 15. Covalent compounds are generally – i) Soluble in water ii) insoluble in water iii) Ionize in water iv) hydrolyse in water 16. Propane with molecular formula C3H8 has – i) 7 covalent bonds ii) 8 covalent bonds iii) 9 covalent bonds iv) 10 covalent bonds 17. A hydrocarbon reacts with ammonical cuprous chloride solution to form a red precipitate, the hydrocarbon is – i) Ethane ii) ethane iii) butane iv) 1-propyne 18. Which of the following substance is added to denature Ethanol? i) Methanol ii) pyridine iii) copper sulphate iv) all of these 19. Which of the following is not an allotropic form of carbon ? i) fluorine ii) fullerene iii) diamond iv) graphite 20. Which of the following represents the correct deceasing order of hydrogen atoms ? i) alkanes, alkenes, alkynes ii) alkanes, alkynes, alkenes iii) alkenes, alkynes, alkanes iv) alkynes, alkanes, alkenes 21. Detergents are sodium or potassium salts of long chain of : i) aldehydes ii) ketones iii) carboxylic acid iv) sulphonic acid Prepared by: M. S. KumarSwamy, TGT(Maths) Page - 44 - 22. In double covalent bond there is a sharing of i) 2 electrons ii) 4 electrons iii) 6 electrons iv) 3 electrons 23. Cation is formed when i) atom gains electrons ii) atom losses electrons iii) proton is lost by the atom iv) atom shared by electrons 24. The total number of electrons that take part in forming a bond in N2 is i) 2 ii) 4 iii) 6 iv) 10 25. Which of the following has the weakest carbon-carbon strength ? i) C2H2 ii) C2H4 iii) C2H6 iv) all have the same bond strength 26. Synthetic flavours contain:- i) unsaturated acids ii) esters iii) dilute carboxylic acids iv) hydroxyl acids 27. Out of the following which one is used as preservative for pickle and sauces:- i) esters ii) acetone iii) aldehyde iv) acetic acid 28. Carbon exists in the atmosphere in the form of (a) carbon monoxide only (b) carbon monoxide in traces and carbon dioxide (c) carbon dioxide only (d) coal 29. Which of the following statements are usually correct for carbon compounds? These (i) are good conductors of electricity (ii) are poor conductors of electricity (iii) have strong forces of attraction between their molecules (iv) do not have strong forces of attraction between their molecules (a) (i) and (iii) (b) (ii) and (iii) (c) (i) and (iv) (d) (ii) and (iv) 30. A molecule of ammonia (NH3) has (a) only single bonds (b) only double bonds (c) only triple bonds Prepared by: M. S. KumarSwamy, TGT(Maths) Page - 45 - (d) two double bonds and one single bond 31. Buckminsterfullerene is an allotropic form of (a) phosphorus (b) sulphur (c) carbon (d) tin 32. Which of the following is the correct representation of electron dot structure of nitrogen? 33. Oils on treating with hydrogen in the presence of palladium or nickel catalyst form fats. This is an example of (a) Addition reaction (b) Substitution reaction (c) Displacement reaction (d) Oxidation reaction 34. In which of the following compounds, — OH is the functional group? (a) Butanone (b) Butanol (c) Butanoic acid (d) Butanal 35. Which of the following are correct structural isomers of butane? (a) (i) and (iii) (b) (ii) and (iv) (c) (i) and (ii) (d) (iii) and (iv) 36. Structural formula of ethyne is Prepared by: M. S. KumarSwamy, TGT(Maths) Page - 46 - 37. Identify the unsaturated compounds from the following (i) Propane (ii) Propene (iii) Propyne (iv) Chloropropane (a) (i) and (ii) (b) (ii) and (iv) (c) (iii) and (iv) (d) (ii) and (iii) 38. Chlorine reacts with saturated hydrocarbons at room temperature in the (a) absence of sunlight (b) presence of sunlight (c) presence of water (d) presence of hydrochloric acid 39. Pentane has the molecular formula C5H12. It has (a) 5 covalent bonds (b) 12 covalent bonds (c) 16 covalent bonds (d) 17 covalent bonds 40. The correct structural formula of butanoic acid is 41. Vinegar is a solution of (a) 50% – 60% acetic acid in alcohol (b) 5% – 8% acetic acid in alcohol (c) 5% – 8% acetic acid in water (d) 50% – 60% acetic acid in water Prepared by: M. S. KumarSwamy, TGT(Maths) Page - 47 - 42. The correct electron dot structure of a water molecule is 43. Which of the following is not a straight chain hydrocarbon? 44. Carbon forms four covalent bonds by sharing its four valence electrons with four univalent atoms, e.g. hydrogen. After the formation of four bonds, carbon attains the electronic configuration of (a) helium (b) neon (c) argon (d) krypton 45. Which of the following does not belong to the same homologous series? (a) CH4 (b) C2H6 (c) C3H8 (d) C4H8 46. The name of the compound CH3 — CH2 — CHO is (a) Propanal (b) Propanone (c) Ethanol (d) Ethanal 47. The heteroatoms present in CH3 — CH2 — O — CH2— CH2Cl are (i) oxygen (ii) carbon (iii) hydrogen (iv) chlorine (a) (i) and (ii) (b) (ii) and (iii) (c) (iii) and (iv) (d) (i) and (iv) 48. The first member of alkyne homologous series is (a) ethyne (b) ethane (c) propyne (d) methane Prepared by: M. S. KumarSwamy, TGT(Maths) Page - 48 - LIFE PROCESSES VERY SHORT ANSWER TYPE QUESTION [1 MARK] 1. What will happen to a plant if its xylem is removed? Answer. Xylem in plant transports water and dissolved mineral nutrients from the roots to all parts of the vascular plant. So, if xylem is removed from the plant, the water and mineral supply to the plant will stop and therefore, the plant will die. 2. Where does digestion of fat take place in our body? Answer. Digestion of fat takes place in the small intestine of our body. 3. Name one accessory pigment and one essential pigment in photosynthetic plants. Answer. Accessory pigment – Carotene/Xanthophyll Essential pigment – Chlorophyll 4. What is the mode of nutrition in human beings? Answer. Holozoic nutrition. 5. Mention the raw materials required for photosynthesis. Answer. The following raw materials are required for photosynthesis: (i) Carbon Dioxide: Plants get CO2 from atmosphere through stomata. (ii)Water: Plants absorb water from soil through roots and transport to leaves. (iii) Sunlight: Sunlight, which is absorbed by the chlorophyll and other green parts of the plant. 6. What would be the consequences of deficiency of hemoglobin in your body? Answer.The deficiency of hemoglobin in our body is called anemia. In anemia, the blood is unable to carry the sufficient amount of oxygen required by the body. So, respiration would be less and less energy will be available to the body. The hemoglobin deficient person will feel weak, pale, lethargic and will be unable to perform heavy physical work. 7. Name the green dot like structures in some cells observed by a student when a leaf peel was viewed under a microscope. What is this green colour due to? Answer. The green dot-like structures in some cells observed by a student when a leaf peel is viewed under a microscope are chloroplasts. The green colour is due to the presence of green pigment, chlorophyll. 8. State any one difference between autotrophic and heterotrophic modes of nutrition. Answer. In autotrophic nutrition, organisms obtain their food from inorganic substances. In heterotrophic nutrition, organisms derive their food from organic substances. 9. Give one reason why multicellular organisms require special organs for exchange of gases between their body and their environment. : Answer. In unicellular organisms the entire body of the organism is in contact with the environment hence exchange of materials can take place but, in multicellular organisms the entire body of the organism is not in contact with the environment and hence simple diffusion is not helpful. 10. Name the process in plants where water is lost as water vapour. : Answer. Transpiration is the process when plants loose water as vapour. Prepared by: M. S. KumarSwamy, TGT(Maths) Page - 49 - 11. What is‘translocation’in plants? Answer. Translocation is the movement of soluble materials, products of photosynthesis from leaves to other tissues throughout the plant. 12. State the basic difference between the

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