Topic: Chemical Kinetics SO HCI 2 + 2I

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PHYSICAL CHEMISTRY by: SHAILENDRA KR. Classes at: - Meq. Approach SCIENCE TUTORIALS; Opp. Khuda Baksh Library, Ashok Rajpath, Patna PIN POINT STUDY CIRCLE; House No. 5A/65, Opp.

1 PHYSICAL CHEMISTRY by: SHAILENDRA KR. Classes at: - Meq. Approach SCIENCE TUTORIALS; Opp. Khuda Baksh Library, Ashok Rajpath, Patna PIN POINT STUDY CIRCLE; House No. 5A/65, Opp. Mahual Kothi, Alpana Market, Patna Topic: Chemical Kinetics 1. The eq.wt.of Na 2 as reductant in the reaction, Na 2 + H 2 O + Cl 2 Na HCI (a) (Mol.wt)/1 (c) (Mol.wt.)/6 (b) (Mol.wt.)/2 (d) (Mol. wt.)/8 2. How many gram of I 2 are present in a solution which requires 40 ml of 0. 11N Na 2 to react with it, + I 2 S 4 + 2I (a) 12.7 g (c) 25.4 g (b) g (d) 11.4 g 3. What weight of Fe (mol. wt. = 152 ) will be oxidised by 200 ml of normal KMnO 4 solution in acid solution: (a) 30.4 g (c) g (b) 60.8 g (d) 15.8 g 4. How many litre of Cl 2 at STP will be liberated by the oxidation of NaCl with 10 g KMnO 4 : (a) 3.54 litre (c) 1.77 litre (b) 7.08 litre (d) None of these 5. The number of mole of ferrous oxalate oxidised by one mole of KMnO 4 (a) 1/5 (b) 3/5 (c) 2/3 (d) 5/3 6. In the reaction, 2 + I 2 S 4 + 2I, the eq. wt. of Na 2 is equal to its: (a) Mol. wt. (b) Mol. wt./2 (c) 2 mol. wt. (d) Mol. wt. / g of a sample of H 2 required 10 ml of N KMnO 4 in a titration in the presence of H 2. Purity of H 2 (a) 25% (b) 85% (c) 65% (d) 95% 8. A 0.50 M solution of KI reacts with excess of H 2 and KI solutions according to the equation, 6H + + 5I + I 3I 2 + 3H 2 O. Which of the following statements is ture: (a) 200 ml of the KI solution react with 0.10 mole KI (b) 100 ml of the KI solution react with M of H 2 (c) 0.5 litre of KI solution produces 0.15 mole of I 2 (d) None 9. When potassium permanganate is titrated against ferrous ammonium sulphate, the equivalent weight of potassium permanganate (a) Molecular weight /10 (b) Molecular weight /5 (c) Molecular weight /2 (d) Molecular weight Page No.: 1

2 10. The number of mole of KMnO 4 that will be needed to react completely with one mole of ferrous oxalate in acidic solution (a) 3/5 (b) 2/5 (c) 4/5 (d) When Br ion react with Br ion in acid solution Br 2 is liberated. The equivalent weight of KBr in this reaction (a) M/8 (b) M/3 (c) M/5 (d) M/6 ( Where M is its molar mass) 12. Hydrogen peroxide in aqueous solution decomoposes on warming to give oxygen according to the equation, 2H 2 (aq) 2H 2 O(l) + (g) under conditions where one mole of gas occupies 24dm 3, 100 cm 3 of XM solution of H 2 produces 3 dm 3 of. Thus X (a) 2.5 (b) 1 (c) 0.5 (d) g aluminium changes to Al 3 + in solution by loosing : (a) electrons (b) electrons (c) electrons g of an oxalate salt was dissolved in 100 ml solution. The solution required 90 ml of N/ 20 KMnO 4 for complete oxidation. The % of oxalate ion in salt (a) 33% (b) 66% (c) 70% (d) 40% 16. Which rate expression suggests an over all order of 0.5 for the reaction involving substances X, Y, Z : (a) Rate = K [X] [Y] [Z] (b) Rate = K [X] 0.5 [Y] 0.5 [Z] 0.5 (c) Rate = K [X] 1.5 [Y] 1 [Z] 0 (d) Rate = K [X] [Y] 0 / [Z] The rate constant (K) for the reaction 2A +B Product was found to be litre mol 1 sec 1 after 15 sec litre mol 1 sec 1 after 30 sec, litre mol 1 sec 1 after 50 scc. The order of reaction (a) 2 (b) 3 (c) Zero (d) The rate constant of a first order reaction is sec 1. At a reactant concentration of 0.02 M, the rate of reaction would be : (a) M sec 1 (b) sec 1 (c) M sec 1 (d) M sec 1 (d) electrons 14. Number of K + ions and number of mole of K + ions present in 1 litre of N/5 KMnO 4 solution respectively in acidic medium are : (a) 0.04 and (b) and 0.04 (c) 200 and (d) and In a first order reaction, the concentration of the reactant is decreased from 1.0 M to 0.25 M in 20 minute. The rate constant of the reaction would be : (a) 10 min 1 (b) min 1 (c) min 1 (d) min Consider the reaction, 2A +B C + D. If the rate expression is rate = K[A] 2 [B] 1 and if concentration of the reactants are increased by three times, the rate of the reaction will increase by : Page No.: 2

3 (a) 9 times (b) 81 times (a) 0.5 M (b) 1.25 M (c) 64 times (d) 27 times (c) 12.5 M (d) 1.0 M 21. An endothermic reaction A B have an activation energy 15 kcal/mol and the heat of the reaction is 5 kcal/mol. The activation energy of the reaction B A (a) 20 kcal/mol (c) 10 kcal/mol (b) 15 kcal/mol (d) Zero 22. The rate of a reaction is doubled for every 10 C rise in temperature. The increase in rate as a result of increase in temperature from 10 C to 100 C (a) 112 (b) 512 (c) 400 (d) For a given reaction of first order, it takes 20 minute for the concentration to drop from 1.0 M litre 1 to 0.6 M litre 1. The time required for the concentration to drop from 0.6 M litre 1 to 0.36 M litre 1 will be : (a) More than 20 minute (b) Less than 20 minute (c) Equal to 20 minute (d) Infinity 24. The specific reation rate constant for a first order reation is sec 1. If the initial concentration of the reactant is 0.01 mole per litre, the rate 26. A first order reaction is carried out with an initial concentration of 10 mole per litre and 80 % of the reactant change into the product. Now if the same reaction is carried out with an initial concentration of 5 mol per litre the percentage of the reactant changing to the product (a) 40 (b) 80 (c) 160 (d) Cannot be calculated 27. The rate constant for a second order reaction is M 1 min 1. How long will it take a 1M solution to be reduced to 0.5 M : (a) Minute (b) minute (c) minute (d) minute 28. For A + B C+D, H = 20kJ mol 1, The activation energy of the forward reaction is 85kJ mol 1. The activation energy for backward reaction is... kj mol 1 : (a) 65 (b) 105 (c) 85 (d) In the following first order competing reactions: A + Reagent Product B + Reagent Product (a) M sec 1 (b) M sec 1 (c) M sec 1 (d) M sec K for a zero order reaction is mol L 1 sec 1. If the concentration of the reactant after 25 sec is 0.5 M, the initial concentration must have been: The ratio of K 1 /K 2 if only 50% of B will have been reacted when 94% of A has been reacted (a) 4.06 (b) (c) 2.06 (d) The rate constant, the activation energy and the Arrhenius parameter of a chemical reaction at 25 C are S 1, kj mol 1 Page No.: 3

4 and S 1 respectively. The value of the rate constant as T is,: (a) S 1 (b) S 1 (c) Infinity (d) s 1 31.The rate constant for the reaction: 2N 2 4N +, is sec 1, if the rate is mol litre 1 sec 1, then the concentration of N 2 mol litre 1 sec 1, then the concentration of N 2 (mol litre 1,) (a) 1.4 (b) 1.2 (c) 0.04 (d) The inversion of cane sugar proceeds with half life of 500 minute at ph = 5 for any concentration of sugar. However, if ph = 6, the half life changes to 50 minute,. The rate law expression for the sugar inversion can be written as: (a) r = k(sugar) 2 (H + ) 0 (b) r = k(sugar) 1 (H + ) 0 (c) r = k(sugar) 1 (H + ) 1 (d) r = k(sugar) 0 (H + ) A compound contains atoms X, Y, Z. The oxidation number of X is +2, Y is +5, and Z is 2. The possible formula of the compound (a) XY 1 Z 2 (b) Y 2 (XZ 3 ) 2 (c) X 3 (YZ 4 ) 2 (d) X 3 (Y 4 Z) In the conversion of Br 2 to Br, the oxidation state of bromine changes from : (a) 0 to +5 (b) 1 to +5 (c) 0 to 3 (d) +2 to +5 (a) 1/5 (b) 2/5 (c) 5/2 (d) When Sn (IV) chloride is treated with excess HCL, the complex [SnCl 6 ] is formed. The oxidation state of Sn in this complex (a) +6 (b) 2 (c) +4 (d) Which reaction indicates the oxidising behaviour of H 2 : (a) 2PCl 5 + H 2 2POCl 3 + 2HCl +S Cl 2 (b) 2NaOH + H 2 Na 2 + 2H 2 O (c) NaCl + H 2 NaH + HCl (d) 2HI + H 2 I 2 + S + 2H 2 O 38. One mole of N 2 H 4 loses 10 mole of electrons to form a new compound Y. Assuming that all nitrogen appears in the new compound, what is the oxidation number of nitrogen in Y (There is no change in the oxidation state of hydrogen): (a) 3 (b) +3 (c) +5 (d) Nitrogen has fractional oxidation number in: (a) N 2 H 4 (b) NH 4 (c) HN 3 (d) N 2 F Oxidation of thiosulphate ( ) ions by iodine gives: (a) S (b) (c) S 4 (d) O The number of mole of oxalate ions oxidised by one mole of MnO 4 Page No.: 4

5 A n s w e r s 01. d 02. b 03. a 04. a 05. d 06. a 07. b 08. c 09. b 10. a 11. c 12. a 13. d 14. b 15. b 16. c 17. a 18. a 19. d 20. d 21. c 22. b 23. c 24. a 25. a 26. b 27. c 28. b 29. a 30. b 31. d 32. b 33. c 34. a 35. c 36. c 37. d 38. b 39. c 40. c Page No.: 5

Topic: Mole Concept. (At. mass, Ba= 137) will be

Topic: Mole Concept. (At. mass, Ba= 137) will be PHYSICAL CHEMISTRY by: SHAILENDRA KR. Meq. Approach Classes at: - SCIENCE TUTORIALS; Opp. Khuda Baksh Library, Ashok Rajpath, Patna PIN POINT STUDY CIRCLE; House No. 5A/65, Opp. Mahual Kothi, Alpana Market,