Chemistry MCQ XII PDF

MCQs ON CLASS 12 CHEMISTRY [Prepared by:K.Sreenivasulu,PGT Chemistry,KV Idukki] 1. Which of following is not a Colligative property? (a)Relative lowering of vapour pressure (b) Elevation in boiling point (c)Osmotic pressure (d) Atmospheric pressure 2. If solute do not un...

MCQs ON CLASS 12 CHEMISTRY [Prepared by:K.Sreenivasulu,PGT Chemistry,KV Idukki] 1. Which of following is not a Colligative property? (a)Relative lowering of vapour pressure (b) Elevation in boiling point (c)Osmotic pressure (d) Atmospheric pressure 2. If solute do not undergo neither association nor dissociation,itsVan’t Hoff factor (i) will be (a)less than unity (b)greater than unity (c)unity (d)zero 3. Who proposed the law of independent migration of ions of an electrolyte? (a) Raoult (b)Van’t Hoff (c)Kohlrausch(d)Hess 4. Units for rate constant (k)for all pseudo first order reactions is (a) mol-1 L s-1 (b) mol-1 L-1 s-1 (c) mol L-1 s-1 (d)s-1 5. Standard electrode potential (E°) for Hydrogen electrode is (a) 0.00V (b)1.00V (c) 0.01V (d) 1.01V 6. Leaching of silver and gold ores are done by (a) NaCN/KCN (b) NaOH/Na2CO3 (c)NaCl/KCl (d)C/CO 7. Half-life of a first order chemical reaction is 5.0 x 10-3sec. What is its rate constant (k1)value? (a)200s-1 (b) 138.6 s-1 (c) 500 s-1 (d)0.005 s-1 8. Denticity of EDTA4- is (a) four (b)six (c)two (d)one 9. DDT is a/an (a) pesticide (b)Insecticide(c) fungicide (d)germicide 10. Which artificial sweetener has limited use (only to cold foods) (a) Aspartame (b) Alitame (c)Saccharin (d)Sucralose Answers: 1.(d) 2.(c) 3.(c) 4.(d) 5.(a) 6.(a) 7.(b) 8.(b) 9.(b) 10.(a)  MULTIPLE CHOICE QUESTIONS – CHEMISTRY CLASS XII – ORGANIC CHEMISTRY 1. The reagent which doesnot react with benzaldehyde is A. NaHSO3 B. Phenyl hydrazine C. Fehling’s solution D. Grignard reagent 2.The IUPAC name of salicylic acid is ………………………. 3. The product formed when phenol is treated with CHCl3 and NaOH is…………………………………………… 4. Two forms of D-glucopyranose are called A. enantiomers B. anomers C. Epimers D. Diastereomers 5. Ketone upon treatment with Grignard reagent gives A. Primary alcohol B. Secondary alcohol C. Tertiary alcohol D. Aldehyde 6. Cyanohydrin of which of the following forms lactic acid A. HCHO B.CH3COCH3 C. CH3CHO D. CH3CH2CHO 7. On heating aniline with chloroform with ethanolic KOH, the product obtained is …………………………………. 8. Reduction of aniline with acetyl chloride in presence of NaOH produce……………… 9. Which one of the following is the strongest base in aqueous solution A. Trimethylamine B. Dimethylamine C. Aniline D. Methylamine 10. What is obtained when acetyl chloride is heated with benzene in presence of anhydrous AlCl3? ANWSERS 1. C 2. 2-Hydroxy benzoic acid 3. Salicylaldehyde 4. B 5. C 6. C 7. Phenyl isocyanide 8. Acetanilide 9. B 10. Acetophenone  CLASS XII- CHEMISTRY MCQ QUESTIONS 1) Among the following cells i)leclanche cell ii)Lead storage battery iii)Mercury cell iv)Nickel-Cadmium cell primary cells are a) i&iv (b) ii&iii (c)I &iii (d) ii &iv 2) The quantity of electricity in coulombs needed to reduce 1 mole of Cr2O7 in the following reaction is Cr2O7 +14H+ +6e-...............>2 Cr3+ +7 H2O a)14F b)2F C)6F d)7F 3) A First order reaction is 50% completed in 1.26*10 14 seconds. How much time would be needed for the completion of 75% of the reaction a)1.26*10 15 b)2.52*10 14s c)2.52*10 28s d) Infinite 4) Extent of adsorption of adsorbate from solution phase increases with ------------- (a) Increase in amount of adsorbate in solution (bDecrease in surface area of adsorbent (c) Increase in temperature of solution (d) Decrease in amount of adsorbate in solution 5) Phenol can be distinguished from ethanl by the reaction with (a) Br2 /H2O (b) Na (c) CHCl3/Aq.KOH (d) Br2/Red.P4 6) For the following compounds i)Aniline ii)P-nitro aniline iii) p—methyl aniline the correct order of increasing basic strength  (a) Ii< II< I (b) III CH3CHO (d) CH3CHO > HCHO > CH3COCH3 Answer: b P BLOCK ELEMENTS ASSERTION - REASON TYPE QUESTIONS 1. Assertion: Oxygen has less negative electron gain enthalpy than Sulphur Reason: Oxygen is more electronegative than Sulphur. 2. Assertion: H2Se is more acidic than H2Te. Reason: Bond enthalpy decrease with increase in atomic size. 3. Assertion: Halogens have characteristic colour. Reason: Halogens readily accept electrons to form halide ion. 4. Assertion: Fluorine forms only one Oxo acid. Reason: Fluorine does not have d orbitals in its valence shell. 5. Assertion: Ozone is a powerful oxidising agent. Reason: Ozone easily decomposes to oxygen gas and oxygen atoms. Answers: 1. Both A and R are correct, but R is not the correct explanation of A 2. Both A and R are correct, R is the correct explanation of A 3. Both A and R are correct, but R is not the correct explanation of A 4. Both A and R are correct, but R is not the correct explanation of A 5. Both A and R are correct, R is the correct explanation of A PARAGRAPH BASED QUESTION A binary compound of oxygen with another element is called oxide. Oxygen reacts with most of the elements of the periodic table to form oxides. In many cases one element forms two or more oxides. The oxides vary widely in their nature and properties. 1. Write the formula of neutral oxides of Nitrogen. 2. Why is Sulphur dioxide called acidic oxide? 3. What is the nature of Aluminium oxide? 4. Which is more acidic , Mn2O7 or MnO2? 5. Generally What is the chemical nature of metal oxides? Answers 1. NO, N2O 2. It dissolves in water to give sulphurous acid. 3. Amphoteric 4. Mn2O7 5. Basic OBJECTIVE TYPE QUESTIONS 1. Sulphur dioxide molecule is ___________ in shape. 2. Name the acid and normal salts of sulphuric acid. 3. What is the hybridisation of Xe in XeF2. 4. Name the main commercial source of Helium. 5. Write the products formed by hydrolysis of ICl. Answers 1. Angular or bent 2. Sulphates and Hydrogen sulphates 3. sp3d 4. Natural gas 5. HCl and HOI MULTIPLE CHOICE QUESTIONS 1. The molecular shape of ClF3 is a. Triagonal planar b. T – Shaped c. Pyramidal d. None of these 2. Ozone is thermodynamically unstable because a. ΔH=+ve, ΔS=-ve b. ΔH=-ve, ΔS=-ve c. ΔH=+ve, ΔS=+ve d. ΔH=-ve, ΔS=+ve 3. Above 1000K, Sulphur shows paramagnetism due to presence of a. S8 b. S6 c. S2 d. S 4. Oleum is a. H2S2O8 b. H2S2O7 c. H2SO3 d. None of the above 5. Composition of Aqua regia is a. Three parts of Conc. HNO3 and one part of Conc. HCl b. Three parts of Conc. HCl and one part of Conc. HNO3 c. One part of Conc. HNO3 and two parts of Conc. HCl d. Two parts of Conc. HNO3 and one part of Conc. HCl  CLASS XII CHEMISTRY 1. The oxidation state of iron on brown ring complex is a ) +1 (b) +3 (c) +2 (d) 0 2. The hybridization of Cu in [Cu(NH3)4 ]+2 is a) Sp3 (b) dsp2 (c) sp3d (d) d2sp2 3. The platinum complex which is used in cancer treatment is a) (b) (c) (d) 4. Name the gas that readily decolorizes acidified potassium dichromate a)CO2 (b)SO2 (c) NO2 (d)P2O5 5. The correct order of adsorption of the following gases on the same mass of charcoal at the same temperature and pressure is a)CH4 p-cresol  10. Unlike Xenon no distinct chemical compound of He is known because a. He is more electro positive b. Chemical reactivity decreases in a group c. He has highest ionisation enthalpy d. Larger size of He atom CHEMISTRY - SET. 2 1. The rate of disappearance of H2 in the following reaction is …. 2. Hybradisation and magnetic character of [NiCl4 ] 2- are (a) dsp2 , paramagnetic (b) dsp2 , diamagnetic , (c) sp3 , paramagnetic ( d) sp3 , diamagnetic 3. Which of the following is incorrect about SO2 (a) It has bleaching action in moist condition (b) It has linear geometry (c) it has both reducing and oxidizing nature (d) its disinfectant in dilute solution 4. The temperature abouve which micelle formation is known as (a) Critical temperature (b) Kraft temperature (c) Boyle temperature (d) Inversion temperature 5. The complex ion having maximum magnitude of ∆o 6. Which of the following compound is least basic (a) NH3 (b) CH3-NH2 (c) C6H5-NH2 (d) (CH3)2NH 7. Which of the following is not an antibiotic (a) Penicillin (b) Ofloxacin (c) Chloramphenicol (d) Tincture of iodine 8. Ethyl amine can be prepared by the action of bromine and NaOH (aq) on which of the following (a) Acetamide (b) Propanamide (c) Formamide (d) Benzamide 9. Which of the following statements is incorrect about the collision theory of chemical reactions (i) It considers reacting molecules or atoms to be hard spheres and ignores their structural features (ii) Number of effective collisions determines the rate of reaction. (iii) Collision of atoms or molecules possessing sufficient threshold energy results into the product formation (iv) Molecules should collide with sufficient threshold energy and proper orientation for the collision to be effective 10 What is the correct order of reactivity of alcohols in the following reactions? R—OH + Conc.HCl + Anhy.ZnCl2 R—Cl + H2O (i) 10 > 20 > 30 (ii) 10< 20 >30 (iii) 30>20>10 (iv) 30 > 10 > 20  CHEMISTRY ( MCQ) Q1.A solution of A contains 7 g/L MgCl2 and solution B contains 7g/L of NaCl. At room temperature, the osmotic pressure of a) solution A is greater than B b) both have same osmotic pressure c) solution B is greater than A d) can’t determine. Q2. The metal which cannot be obtained by the electrolysis of aqueous solution of its salt is a) Cr b) Ag c) Ca d) Cu Q3. The time taken for 10% completion of a first order reaction is 20 min. Then for 19% completion, the reaction will be a) 40 mins b) 60 mins c) 30 mins d) 50 mins Q4. Gelatine is mostly used in making ice creams in order to a) prevent colloidal sol formation b) enrich the fragrance Q5. Which of the following ore is best concentrated by froth floatation method. a) Magnetite b) Galena c) Siderite d) Malachite Q6. Which among the following is most reactive ? a) I2 b) ICl c) Cl2 d) Br2 Q7.The actinoids exhibit more number of oxidation states in general than the lanthanoids. This is because a) the 4f orbitals extend farther from the nucleus than the 4f orbitals. b) the 5f orbitals are more buried than the 4f orbitals c) there is similarity between 4f & 5f orbitals in their angular part of their wave function. d) the actinoids are more reactive than lanthanoids. Q8. The oxidation number & coordination number of Ag in Tollens reagent respectively are a) 1,1 b)2,1 c) 2,2 d) 1,2 Q9.Which of the following alkyl halides will undergo SN1 reaction most readily? a) (CH3)3C-F b) (CH3)3C-Cl c) (CH3)3C-Br d) (CH3)3C-I Q10. Which of the following cannot be used to oxidise primary alcohol to aldehydes? a) CrO3 in anhydrous medium b) pyridinium chlorochromate c) KMnO4 in acidic medium d) Heating in presence of Cu at 573 K Q11.C3H6O did not give a silver mirror with Tollen’s reagent, but gave an oxime with hydroxylamine.It can give positive a) iodoform test b) Fehling,s test c) Schiff’s test d) carbylamines test. Q12..Which one of the following can be prepared by Gabriel phthalimide synthesis. a) Aniline b) o-Toluidine c) Benzylamine d) 4-Bromoaniline. Q13.The two forms of D-glucopyranose are called a) diastereomers b) anomers c) epimers d) enantiomers Q14. Which polymer is used used in the manufacture of paints and lacquers? a) polypropene b) polyvinylchloride c) Bakelite d) Glyptal Q15.Compound which is added to soap to impart antiseptic properties is a) sodium lauryl sulphate b) sodium dodecylbenzene sulphonate c) rosin d) bithional Assertion reason type Questions Directions: Each question contains STATEMENT- 1 (Assertion) and STATEMENT –2 (Reason). Each question has 4 choices (a), (b) , (c) & (d) out of which only one is correct. Choose the correct option as under: (a) Statement –1 is true, Statement – is true & Statement 2 is the correct explanation of statement -1 (b)Statements 1 &2 are true: Statement-2 is not a correct explanation for statement-1 (c) Statement -1 is true & statement 2 is false.d) Statement -1 is false & Statement -2 is true. Q16.Assertion: Addition of non-volatile solute to a volatile solvent increases the boiling point. Reason: Addition of non-volatile solute results in lowering of vapour pressure. Q17.Assertion: Al2O3 is converted into aluminium by reduction with carbon. Reason: Carbon(graphite) has greater affinity for oxygen than aluminium. Q18.Assertion: To a solution of potassium chromate ,if a strong acid is added,it changes its colour from yellow to orange. Reason: The colour change is due to change in oxidation state. Q19. Assertion : Benzaldehyde is less reactive than ethanal towards nucleophilic attack. Reason :All carbon atoms of benzaldehyde are sp2 hybridised. Q20.Assertion: p-Nitrophenol is more acidic than o- Nitrophenol. Reason: Intramolecular hydrogen makes o-isomer weaker than p-isomer.