Karnataka 1 Year PUC Chemistry Model Question Paper 2023-24 PDF

GOVERNMENT OF KARNATAKA KARNATAKA SCHOOL EXAMINATION & ASSESSMENT BOARD Class: I Year PUC MODEL QUESTION PAPER Academic Year: 2023-24 Subject: Chemistry (34) Maximum Marks: 70 Time: 3.15hours Number of que...

GOVERNMENT OF KARNATAKA KARNATAKA SCHOOL EXAMINATION & ASSESSMENT BOARD Class: I Year PUC MODEL QUESTION PAPER Academic Year: 2023-24 Subject: Chemistry (34) Maximum Marks: 70 Time: 3.15hours Number of questions: 52 Instructions: 1. Question paper has FIVE parts having 52 questions. All parts are compulsory. 2. a. Part-A carries 20 marks. Each question carries 1 mark. b. Part-B carries 10 marks. Each question carries 2 marks. c. Part-C carries 18 marks. Each question carries 3 marks. d. Part-D carries 10 marks. Each question carries 5 marks. e. Part-E carries 12 marks. Each question carries 3 marks. 3. In Part- A questions, first attempted answer will be considered for awarding marks. 4. Write balanced chemical equations and draw neat labelled diagrams and graphs wherever necessary. 5. Direct answers to the numerical problems without detailed steps and specific unit for final answer will not carry any marks. 6. Use log tables and simple calculator if necessary (use of scientific calculator is not allowed). PART-A I. Select the correct option from the given choices: 15 × 1= 15 1. The number of significant figures in 0.523 is a) 3 b) 4 c) 2 d) 1 2. Molarity is defined as the number of moles of solute present in a) one litre of solution b) one litre of solvent c) one kg of solution d) one kg of solvent 3. Rutherford’s α - ray scattering experiment is related to the size of the a) nucleus b) atom c) electron d) neutrons 4. Mendeleev`s periodic table is based on a) atomic weight b) atomic number c) number of neutrons d) number of electrons 5. In XeF4 molecule, number of lone pairs and shared pairs of electrons respectively are a) 4, 1 b) 2, 4 c) 4, 3 d) 4, 2 6. Which of the following is true for ionic compounds? a) conduct electricity in solid state b) have directional bonds c) soluble in polar solvents d) are non-electrolytes in molten state 7. The second law of thermodynamics introduced the concept of: a) enthalpy b) work c) entropy d) internal energy 8. The difference between heat of reaction at constant pressure and heat of reaction at constant volume is greater than RT when a) Δng = 1 b) Δng > 1 c) Δng < 1 d) Δng ≠ 1 I PU CHEMISTRY (34) MODEL PAPER 23-24 Page 1 9. If a catalyst is used in a reversible reaction, a) backward reaction becomes faster b) forward reaction becomes faster c) equilibrium constant decreases d) equilibrium is attained more quickly 10. Lewis acids are a) proton donors b) electron pair acceptors c) electron pair donors d) proton acceptors 11. During reduction, oxidation number a) increases b) decreases c) do not changes d) depends on the reaction 12. The property catenation is more marked in the case of a) silicon b) carbon c) tin d) copper 13. Methoxy methane and ethyl alcohol are a) position isomers b) chain isomers c) functional isomers d) metamers 14. According to Markownikoff’s rule, when hydrogen halides add to an unsymmetrical alkene, the hydrogen of HX attaches to a) carbon at the end of the molecule b) carbon in the middle of the molecule c) carbon with least number of hydrogen atoms d) carbon with maximum number of hydrogen atoms 15. Which of the following hydrocarbon damage DNA and cause cancer in the human body a) 1,2-Benzanthracene b) 1,2-Benzpyrene c) 3-Methylcholanthrene d) all of these II. Fill in the blanks by choosing the appropriate word from those given in the brackets: (aromatisation, zero, increases, 8 electrons, - CH2-, - CH3) 5 × 1 =5 16. The outer shell of the most stable atoms contains __________. 17. The standard enthalpy of formation of element is taken as ____________ by convention. 18. When the pH of a solution decreases, its hydrogen ion concentration is ________. 19. In a homologous series of aliphatic hydrocarbons, the successive members differ from each other in molecular formula by a _______ group. 20. n-Hexane on heating to 773K, under 10-20atm pressure in the presence of oxides of vanadium, molybdenum forms benzene. The process is called ___________. PART - B III. Answer any five of the following. Each question carries two marks. 5 × 2 = 10 21. Define entropy? What happens to the entropy when liquid changes into vapour? 22. What is the heterogeneous equilibrium? Give an example. 23. What are isoelectronic species? Select isoelectronic pair among the following: Na+, Cl-, F-, Li+ 24. Give any two limitations of octet rule. I PU CHEMISTRY (34) MODEL PAPER 23-24 Page 2 25. Define hydrogen bond? Name a compound having intra molecular H-bond. 26. Helium is monoatomic. Explain on the basis of Molecular Orbital Theory. 27. Using the stock notation, represent the following compound (i) HauCl4, (ii) Fe2O3. 28. For the compound CH ≡ C – CH = CH – CH3 i) Write the bond-line formula for the above compound. ii) Mention whether the compound is saturated or unsaturated? 29. Write geometrical isomers of but-2-ene. PART - C IV. Answer any three of the following. Each question carries three marks. 3 × 3 = 09 30. Define electronegativity of an element. How does it vary along a period and down a group in the periodic table? 31. Explain the shape of ammonia molecule using VSEPR theory? 32. a. Define dipole moment. What is its unit? b. Sigma bond is stronger than pi bond. Give reason. 33. Write Lewis dot structure for NO2- molecule. Calculate the formal charge on each oxygen atoms present in it. 34. Balance the chemical equation by oxidation number method (in acidic medium) Fe+2 + MnO4- → Fe+3 + Mn2+ V. Answer any three of the following. Each question carries three marks. ̳3 × 3 = 09 35. Write the any three postulates of Dalton’s atomic theory. 36. Write any three limitations of Bohr model of an atom. 37. For the element with atomic number 24. i) Write the electronic configuration ii) How many unpaired electrons present in it? iii) To which block of the periodic table it belongs? 38. Derive the relationship between Cp and Cv for an ideal gas. 39. State Lechatlier’s principle. What is the effect of temperature on the equilibrium if the reaction is exothermic? 40. How are Kp and Kc related? Give one reaction each in which (i) Kp > Kc (ii) Kp = Kc PART - D VI. Answer any two of the following. Each question carries five marks. 2 × 5 = 10 41. a) What is the type of hybridisation of carbon atoms marked as a, b and c in the following compound? H3Ca – HCc = Cb = CH2. b) What is carbocation? Write the decreasing order of stability among 10, 20 and 30 carbocations. (3 + 2) 42. a) Explain the principle and calculations involved in the estimation of carbon in the organic compound. b) What are electrophiles? (4 + 1) I PU CHEMISTRY (34) MODEL PAPER 23-24 Page 3 43. a) An alkene ‘A’ on ozonolysis gives a mixture of ethanal and propan-2-one. Write the chemical reaction and IUPAC name of ‘A’. b) Explain Wurtz reaction with a suitable example. (3 + 2) 44. a) Explain the mechanism of nitration of benzene. b) Draw the staggered conformation of ethane. (3 + 2) VII. Answer any four of the following. Each question carries three marks. 4 × 3 = 12 45. An Organic compound contains 26.66% carbon, 2.22% hydrogen and 71.12% oxygen. The molecular mass of the compound is 90. Find molecular formula. 46. Dinitrogen and dihydrogen react with each other to produce ammonia according to the following chemical equation. N2(g) + 3H2(g) 2NH3 (g) Calculate the mass of ammonia produced if 2 × 103 g dinitrogen reacts with 1 × 103 g of dihydrogen. 47. Calculate the wave number and wave length of first line in Balmer series of hydrogen spectrum. (Given: RH = 1.09677 X 107 m -1) 48. Calculate the energy of one mole of photon of radiation whose frequency is 5x1014 Hz. 49. The standard enthalpies of combustion of carbon, hydrogen and C6H6 are -393.5 kJmol-1, -285.83 kJmol- 1 and -3267 kJmol-1 respectively. Calculate the standard enthalpy of formation of C6H6. 50. Calculate the total work done when one mole of a gas expands isothermally and reversibly from an initial volume of 10 dm3 to a final volume of 20 dm3 at 298 K. (R = 8.314 JK-1 mol-1) 51. Calculate ∆G0 for the hydrolysis of sucrose. The equilibrium constant KC is 2 × 10-3 at 300 K. (R = 8.314 JK-1 mol-1) 52. Reaction between N2 and O2 take place as follows 2N2(g) + O2(g) 2N2O (g) If a mixture of 0.482 mol of N2 and 0.933 mol of O2 is placed in a 10L vessel and allowed to form N2O at a room temperature at which Kc = 2 × 10-37, determine the composition of equilibrium mixture. I PU CHEMISTRY (34) MODEL PAPER 23-24 Page 4