ASSERTION REASON

In each sub-question below a statement S and an explanation E is given. Choose the correct answers from the codes A,B,C,D given for each question.

(A) Statement-1 is true, statement-2 is true and statement-2 is correct explanation for state- ment-1

(B) Statement-1 is true, statement-2 is true and statement-2 is NOT the correct explanation for statement-1

(C) Statement-I is false, statement-2 is true. (D) Statement-1 is true, statement-2 is false. 16. Statement-1 : Water boils at high temperature in

pressure cooker.

Statement-2 : Increase in pressure leads to an increase in boiling point.

Sol.

17. Statement-1 : A decrease in pressure leads to an increase in freezing point of water.

Statement-2 : For ice on melting volume decreases.

Sol.

18. Statement-1 : The solubility of gases always increases with increase in pressure.

Statement-2 : High pressure favours the change where volume of gas decreases.

Sol.

19. Statement-1 : Total number of moles in a closed system at new equilibrium is less than the old equilibrium if some amount of a substance is re- moved from a system.

A(g) B(g) equilibrium.

Statement-2 : The number of moles of the sub- stance which is removed, is partially compen- sated as the system reached to new equilib- rium.

Sol.

20. Statement-1 : An exothermic reaction, non- spontaneous at high temperature, may become spontaneous at low temperature.

Statement-2 : Entropy of an exothermic reac- tion always decrease with decrease in tempera- ture.

21. Statement-1 : Ammonia at a pressure of 10 atm and CO₂ at a pressure of 20 atm are intoduced into an evacuated chamber. If K_p for the reac- tion.

NH₂COONH₄(s) 2NH₃(g) + CO₂(g) is 2020 atm3_{, the total pressure after a long time is less}

than 30 atm.

Statement-2 : Equilibrium can be attained from both directions.

Sol.

COMPREHENSION

Paragraph for Questions No. 22 to 25

In a 7.0 L evacuated chamber, 0.50 mol H₂ and 0.50 mol I₂ react at 427°C

H₂(g) + I₂ (g) 2HI(g). At the given tem- perature, K_c = 49 for the reaction.

22. What is the value of K_p ?

(A) 7 (B) 49

(C) 24.5 (D) None

Sol.

23. What is the total pressure (atm) in the chamber

(A) 83.14 (B) 831.4

(C) 8.21 (D) None

Sol.

24. How many moles of the iodine remain unreacted at equilibrium ?

(A) 0.388 (B) 0.112

(C) 0.25 (D) 0.125

Sol.

25. What is the partial pressure (atm) of HI in the equilibrium mixture ?

(A) 6.385 (B) 12.77 (C) 40.768 (D) 646.58 Sol.

Pragraph for Question Nos. 26 to 28

Equilibrium constants are given (in atm) for the following reactions at 0°C :

SrCl₂. 6H₂O(s) SrCl₂ . 2H₂O(s) + 4H₂O(g) K_p = 5 × 10–12

Na₂HPO₄.12H₂O(s) Na₂HPO₄. 7H₂O (s) + 5H₂O(g)K_p = 2.43 × 10–13

Na₂SO₄.10H₂O(s) Na₂SO₄(s) + 10 H₂O(g) K_p = 1.024 × 10–27

The vapour pressure of water at 0° C is 4.56 torr. 26. Which is the most effective drying agent at 0°C ?

(A) SrCl₂.2H₂O (B) Na₂HPO₄. 7H₂O (C) Na₂SO₄ (D) all equally Sol.

27. At what relative humidities will Na₂SO₄. 10 H₂O be efflorescent (release moisture) when exposed to air at 0°C ?

(A) above 33.33 % (B) below 33.33 % (C) above 66.66% (D) below 66.66% Sol.

28. At what relative humidities will Na₂SO₄ be deliquescent (i.e. absorb moisture) when exposed to the air at 0°C?

(A) above 33.33 % (B) below 33.33 % (C) above 66.66% (D) below 66.66% Sol.

Paragraph for Question Nos. 58 to 60

If we know the equilibrium constant for a par- ticular reaction, we can calculate the concen- trations in the equilibrium mixture from the initial ocncentrations. Commonly only the initial con- centration of reactants are given.

29. In a study of equilibrium H₂(g) + I₂(g) 2HI (g)

1 mole of H₂ and 3 mole of I₂ gave rise at equilib- rium to x mol of HI.

Addition of a further 2 mol of H₂ gave an addi- tional x mol of HI. What is x ?

(A) 0.5 (B) 1

(C) 1.5 (D) None of these

Sol.

30. In above prolem, what is K_p at the temperature of the experiment. (A) 1 (B) 2 (C) 4 (D) None of these Sol. 31. In a study of equilibrium 2SO₂(g) + O₂(g) 2SO₃(g)

Starting with 2 mole SO₂ and 1.5 mole O₂ in 5 litre flask. Equilibrium mixture required 0.4 mole KMnO₄ in acidic medium. Hence K_c is :

(A) 0.2 (B) 5.0

(C) 675.0 (D) None of these Sol.

Match the column 32. Column I (A) K_p < K_c (B) Introduction (C) 0 P K is dimensionless (D) Temperature increase Column II (P)N₂+3H₂ 2NH₃ (Q) PCl₅(g) PCl₃(g) + Cl₂(g) of inert gas at pressure will decrease the constant con centration of reactants.

(R) 2NO₂(g) N₂O₄(g)

(S) NH₃(g) + HI (g) will shift the reaction NH₄I (s) on product side.

33. Column-I Column-II Kp/Kc (A) A_2(g)+3B_2(g) 2AB_3(g) (p) (RT)–2 (b) A_2(g)+B_2(g) 2AB_(g) (q) (RT)0 (C) A_(s)+1.5B_2(g) 2AB_3(g) (r) (RT)½ (D) AB_2(g) AB_(g)+0.5B_2(g) (s) (RT)–½ Sol. 34. Column-I (A) A_2(g)+B_2(g) Exothermic 2AB_(g) (B) 2AB_2(g)+B_2(g) Exothermic 2AB_3(g) (C) 2AB_3(g) Exothermic A_2(g)+3B_2(g)

Column-II factors affecting forward (p) High temperature (q) Low temperature (r) High pressure (s) Low pressure (t) Independent of pressure INTEGER TYPE

35. If a mixture of 3 mole of H₂ and 1 mole of N₂ is completely converted into NH₃, what would be the final volume at same p and T ?

Sol.

36. For the reaction, C(s)+CO₂(g) 2CO(g), the partial pressure of CO₂ and CO are 2.0 atm and 4.0 atm respectively at equilibrium. Find the K_p for the reaction.

Sol.

37. In the reaction, PCl₅ PCl₃+Cl₂, the amounts of PCl₅, PCl₃ and Cl₂, 2 moles each at equilibrium and the total pressure is 3 atm. Find the equilibrium constant K_p.

Sol.

38. For the equilibrium, 2NO_(g)+O2_(g) 2NO_2(g), K_p is 1.24×10–2 _{at 727°C. Find the value of K}

C at

727°C. Sol.

39. The equilbrium constant for, 2H₂S_(g) 2H_2(g) +S_2(g) is 0.469 atm at 1065°C and heat of dissociation is 42.4 kcal. Calculate the equilbrium constant at 1132°C.

Sol.

40. The molar concentration of A and B are 0.80 mol litre each. On mixing them, the reaction starts to proceed as : A+B c+D, and attain equilbrium. At equilibrium molar concentration of C is 0.60 mol/litre. Find the value of K_C of the reaction. Sol.

41. In a reaction at equilibrium 'x' mole of the reactant A decompose to give 1 mole of C and D.It has been found that the fraction of A decomposed at equilibrium is indepent of inital concentration of A. Find the value of x.

42. In the reaction C(s)+ CO₂(g) 2CO(g), the equilbrium pressure is 6.75 atm. If 50% of CO₂ reacts, then find the value of K_p.

Sol.

43. N₂O₄ is 60% dissociated into NO₂ at 340K and 1 atm pressure. Find the volume of 10 g N₂O₄ occupy under these condition.

Sol.

44. Ammonium carbamate when heated to 473K gives a mixture ofNH₃ and CO₂ vapour with a density of 13. Find the degree of dissociation of ammonium carbamate.

Sol.

45. In a experiment starting with 1 mole of C₂H₅OH, 1 mole of CH₃COOH and 1 mole of water, the equilbrium mixture on analysis shows that 54.3% of the acid is esterified. Find the value of K_C. Sol.

46. Maximum number of phases at equilibrium of pure substance is

Sol.

47. The composition of the equilibrium mixture for the equilibrium Cl₂ 2Cl at 14700_{K, may be}

determined by the rate of diffusion of mixture through a pin hole. It is found that at 14700_K,

the mixture diffuses 1.16 times as fast as kryp- ton (83.8) diffuses under the same conditions. Calculate the % degree of dissociation of Cl₂ at equilibrium.

Sol.

48. 2A(g) + B(g) Keq.=2×10 9

3C(g)

Initially only A & B are present in the container & moles of A and B at t = 0 are 4 & 2 respectively. If the concentration of A at equilibrium is p × 10–q _{then find p + q – 2}

Given : Volume of container is 100 lit. Sol.

49. Ammonium carbamate dissociates as NH₂COONH₄ (s) 2NH₃ (g) + CO₂(g). In a closed vessel containing ammonium carbamate in equilibrium, ammonia is added such that partial pressure of NH₃ now equals to the original total pressure. Calculate the ratio of total pressure now to the original pressure as P/Q and give P + Q.

Sol.

50. In a study of the reaction 2A + 2B 3C + D, A and B are mixed in a vessel at t0_{C. The initial}

conc. of A is twice the initial conc. of B. After equilibrium is reached, the conc of C is three times the conc. of B. Calculate the equilibrium constant K_C in terms of P/Q and report P + Q.