## NCERT Class 11 Chemistry Equilibrium Multiple Choice Questions

**Question 1. Some reactions, their equilibrium constants are as follows:**

⇒ \(\mathrm{CO}(\mathrm{g})+\mathrm{H}_2 \mathrm{O}(\mathrm{g}) \rightleftharpoons \mathrm{CO}_2(\mathrm{~g})+\mathrm{H}_2(\mathrm{~g}) ; K_1\)

⇒ \(\mathrm{CH}_4(\mathrm{~g})+\mathrm{H}_2 \mathrm{O}(\mathrm{g}) \rightleftharpoons \mathrm{CO}(\mathrm{g})+3 \mathrm{H}_2(\mathrm{~g}) ; K_2 \)

⇒ \(\mathrm{CH}_4(\mathrm{~g})+2 \mathrm{H}_2 \mathrm{O}(\mathrm{g}) \rightleftharpoons \mathrm{CO}_2(\mathrm{~g})+4 \mathrm{H}_2(\mathrm{~g}) ; K_3\)

**The relation among K _{1}, K_{2} and K_{3} is**

- \(K_3 \times K_2^3=K_1^2\)
- \(K_1 \sqrt{K_2}=K_3\)
- K
_{2}× K_{3}= K_{1} - K
_{3}= k_{1}× k_{2}

**Answer:** 4. K_{3} = k_{1 }× k_{2}

**Question 2. At a given temperature, the reaction, A(g) 20(g), is In equilibrium In a closed flask. At the same temperature, the reaction, C(g) D(g) + O(g) Is in equilibrium in another closed flask. The values of equilibrium constants of these two reactions are Kp and Kp respectively and the total pressures of the equilibrium mixtures are P _{1} and P_{2} respectively. If: Kp_{2} =1:4 and P_{1} P_{2} = then the ratio of the degree of dissociation of (g) and C(g) are (assume the degrees of dissociation of body care very small compared to **

- 0.15
- 0.5
- 1.0
- 1.5

**Answer:** 2. 0.5

**Question 3. At a given temperature, the reaction, A _{2}(g) + B_{2}(g) 2A_{2}(g) was started with 0.4 mol of A_{2}(g) and 0.0 mol of H_{2}(g) in a flask of volume 2L. When the reaction achieved equilibrium, it was found that the reaction mixture contained 0.5 mol of AO. (The equilibrium constant ( Kp) for the reaction is**

- 8.30
- 4.76
- 10.27
- 6.49

**Answer:** 2. 4.76

**Question 4. At a given temperature, if the degree of dissociation of N _{2}O_{4 }in the following reaction N_{2}O_{4}(g) 2NO_{2}(g) is a, and the total pressure of the equilibrium mixture is P, then it can be shown that the equilibrium constant for the reaction, K_{p}= a_{2}P (assuming a is very small compared to 1). Which ofthe following comments is true for this relation**

- K
_{p}increases as a increases - K
_{p}increases as P increases. - value of Kp does not depend on P but depends on a
- The value of Kp depends neither on P nor on a

**Answer:** 4. The value of Kp depends neither on P nor on a

**Question 5. For the reactions**

** ⇒ \( \mathrm{N}_2(g)+3 \mathrm{H}_2(g) \rightleftharpoons 2 \mathrm{NH}_3(g),\) **

**⇒ \(\mathrm{N}_2(\mathrm{~g})+\mathrm{O}_2(\mathrm{~g}) \rightleftharpoons 2 \mathrm{NO}(\mathrm{g}) \& \mathrm{H}_2(\mathrm{~g})+\frac{1}{2}\mathrm{O}_2(\mathrm{~g}) \rightleftharpoons \mathrm{H}_2 \mathrm{O}(\mathrm{g}) \text {, }\) **

**If the equilibrium constants are K _{1}, K_{2} and K_{3} respectively, then the equilibrium constant for the reaction \(4 \mathrm{NH}_3(g)+5 \mathrm{O}_2(\mathrm{~g}) \rightleftharpoons 4 \mathrm{NO}(\mathrm{g})+6 \mathrm{H}_2 \mathrm{O}(\mathrm{g})\) is**

1. \(\frac{K_2 K_3^2}{K_1}\)

2. \(\frac{K_2^2 K_3^2}{K_1}\)

3.\(\frac{K_1^3 K_2^2}{K_3}\)

4. \(\frac{K_2^2 K_3^6}{K_1^2}\)

**Answer:** 4. \(\frac{K_2^2 K_3^6}{K_1^2}\)

**Question 6. For a hypothetical reaction, K _{c} = 0.9 and K_{p} = 538. Which of the following equations pan represents the reaction properly at 25°C-**

- \(A(g) \rightleftharpoons 2 C(s)+D(g)\)
- \(B(g) \rightleftharpoons C(l)+D(l)\)
- \(A(l)+2 B(g) \rightleftharpoons 2 C(g)\)
- \(A(g)+B(s) \rightleftharpoons 3 C(g)\)

**Answer:** 4. \(A(l)+2 B(g) \rightleftharpoons 2 C(g)\)

**Question 7. When a mixture containing N _{2} and H_{2} in the molar ratio 1:3 heated in the presence of a catalyst in a closed vessel, die following equilibrium is established: **

**⇒ \(\mathrm{N}_2(g)+3 \mathrm{H}_2(g) \rightleftharpoons 2 \mathrm{NH}_3(g)\) **

**At equilibrium, if the mole fraction of NH _{3 }is 0.6 and the total pressure ofthe equilibrium mixture is 10 atm then Kp for the reaction, \(2 \mathrm{NH}_3(g) \rightleftharpoons \mathrm{N}_2(g)+3 \mathrm{H}_2(g)\)**

- 1.33 atm
^{-2} - 0.75 atm
^{-2} - 1.333 atm
^{-2} - 0.75 atm
^{-2}

**Answer:** 1. 1.33 atm^{-2}

**Question 8. The reaction, \(A(g)+4 B(g) \rightleftharpoons 2 C(g)+3 D(g)\) is carried out in a closed vessel of volume 2L by taking 3 mol of A(g) and 4 mol of 5(g). At equilibrium, if the amount of C(g) be1 mol, then Kc for the reaction is**

- 0.056
- 0.038
- 0.084
- 1.24

**Answer:** 3. 0.084

**Question 9. The total pressure at the equilibrium of the reaction, XY(g) X(g) + Y(g) is P. If the equilibrium constant P for the reaction is Kp and \(K_p=\frac{P}{8}\), then the percent dissociation of XY is**

- 30.49%
- 33.33%
- 41.90%
- 19.26%

**Answer:** 2. 33.33%

**Question 10. At 500K, for the reaction, PCl _{5}(g) PCl_{3}(g) + Cl_{2}(g) , the equilibrium constant, Kp = 0.52 . In a closed container, these three gases are mixed. If the partial pressure of each of these gases is 1 atm, then in the reaction system.**

- The number of moles of PCl
_{5}will increase - The number of moles of PCl
_{3}will increase - The reaction will attain equilibrium when 50% of the reaction gets completed
- The reaction will attain equilibrium when 75% of the reaction is completed

**Answer:** 1. The number of moles of pcl_{5 }will increase

**Question 11. For the reaction: \(2 A(g)+B(g) \rightleftharpoons 3 C(g)+D(g)\), two moles of each A and B were taken into a flask which of the following relation between the concentration terms is true when the system attains equilibrium**

- [A]=[B]
- [A]<[B]
- [A]=[B]
- [A]>[B]

**Answer:** 2. [A]<[B]

**Question 12. The reaction, 2A(g) + 5(g) C(s); ΔH < 0, is in equilibrium in a closed vessel. Which of the following changes at equilibrium’ will increase the yield of C (s)**

- Temperature is increased
- At constant volume and temperature, some amount of 5(g) is added to the reaction system
- At constant volume and temperature, some amount of c (s) is removed from the reaction system noriw
- Pressure is decreased at a constant temperature

**Answer:** 2. At constant volume and temperature, some amount of 5(g) is added to the reaction system.

**Question 13. At 300 K, the reaction A(g) + 5(g) C(s), 1 is in equilibrium in a closed, vessel. At the beginning of the reaction, the partial pressures of A and B gases are 0.2 and 0.3atm respectively and the total pressure of the equilibrium mixture is 0.3atm. Kc, for the reaction, is—**

- 6.06 ×10
^{4}L^{2}.mol^{-2} - 2.59 × 10
^{3}L^{2}.mol^{-2} - 3.03 ×10
^{4}L^{2}.mol^{-2} - 8.2 ×10
^{2}L^{2}.mol^{-2}

**Answer:** 3. 3.03 × 10^{4} L^{2}.mol^{-2}

**Question 14. At 300K, for the reaction, \(\mathrm{AB}_3(\mathrm{~g}) \rightleftharpoons \mathrm{AB}_2(\mathrm{~g})+\frac{1}{2} \mathrm{~B}_2(\mathrm{~g}),\) Kp = 1.66. At the same temperature, ΔG° for the reaction, 2AB _{2}(g) + B_{2}(g) 2AB_{3}(g) is**

- +2.19kJ
- -2.52KJ
- +3.85KJ
- -3.26kJ

**Answer:** 2. -2.52KJ

**Question 15. At a given temperature, when a reversible reaction is carried out in the absence of a catalyst, the ratio of the rate constants for the forward and reverse reactions is found to be 8.0. At the same temperature, if the reaction is carried out in the presence of a catalyst, then the ratio will be**

- >8.0
- <8.0
- =8.0
- <8.0

**Answer:** 3. =8.0

**Question 16. At a given temperature, a closed vessel contains NH _{3} gas and solid NH_{4}HS. The pressure of NH_{3} gas in the vessel is 0.50 atm. On dissociation, NH_{4}HS produces NH_{3} and H_{2}S gases. The total pressure in the flask at equilibrium is 0.84 atm. The equilibrium constant for the dissociation reaction (Kp) of NH_{4}HS is**

- 0.30 atm
^{-2} - 0.16 atm
^{-2} - 0.11 atm
^{-2} - 0.22 atm
^{-2}

**Answer:** 3. 0.11 atm^{-2}

**Question 17. N _{2}O_{4} is dissociated to 33% and 40% at total pressures P_{1} and P_{2} atm respectively. Hence, the ratio of P_{1} to P_{2} is**

- \(\frac{7}{3}\)
- \(\frac{8}{3}\)
- \(\frac{8}{5}\)
- \(\frac{7}{4}\)

**Answer:** 3. \(\frac{8}{5}\)

**Question 18. The reaction, A(g) + 25(g) 2C(g) + D(g) was studied using an initial concentration of 5 which was 1.5 times that of. The equilibrium concentrations of A and C were found to be equal. So, Kc for the equilibrium is**

- 4
- 0.32
- 2.73
- 8.17

**Answer:** 2. 0.32

**Question 19. The equilibrium constants Kp _{1} and Kp_{2} for the reactions x ⇌ 2y and x ⇌ p + q, respectively are in the ratio of 1: 9 . If the degree of dissociation and Z is equal then the ratio of total pressure at this equilibrium is**

- 1:36
- 1:1
- 1:3
- 1:9

**Answer:** 1. 1:36

**Question 20. If the equilibrium constant for Mutrotion or-D-glucose is the percentage ofthe a – form in the equilibrium mixture is**

- 64.5
- 35.7
- 53.7
- 44.8

**Answer:** 2. 35.7

**Question 21. The reaction, C(s) + CO _{2}(g) ⇌ 2CO(g), is at equilibrium in a closed vessel under a given set of conditions. If the degree of dissociation of CO_{2} at equilibrium is a and the total pressure of the equilibrium mixture and the value of equilibrium constant are P and Kp respectively, then a**

1. \(\frac{K_p}{\sqrt{2 P}}\)

2. \(\frac{1}{2} \sqrt{\frac{K_p}{p}}\)

3. \(\frac{\sqrt{K_p}}{P}\)

4. \(\sqrt{\frac{P}{K_p}}\)

**Answer:** 4. \(\sqrt{\frac{P}{K_p}}\)

**Question 22. At a given temperature, the equilibrium constant, Kc, for the reaction, A + B C is 10. At the same temperature, the reaction is allowed to occur in a closed vessel of volume 1L. At a particular moment during the reaction, if the amounts of A, B, and C in the reaction system are 0.1, 0.4, and 0.3 mol respectively, then**

- The reaction is in equilibrium at that moment
- The reaction will occur to a greater extent towards the left to attain equilibrium
- The reaction will occur to a greater extent towards the right to attain equilibrium
- The reaction will occur to a greater extent towards the left for achieving equilibrium and concentrations of reactants and product will be the same at a new equilibrium

**Answer:** 3. The reaction will occur to a greater extent towards the right to attain equilibrium

**Question 23. A mixture containing N _{2} and H_{2} in a mole ratio of 1: 3 is allowed to attain equilibrium when 50% ofthe mixture has reacted. If P is the pressure at equilibrium, then the partial pressure of NH_{3} formed is**

- p/3
- p/2
- p/9
- p/5

**Answer:** 1. p/3

**Question 24. If the concentration of OH ^{–} ions in the reaction Fe(OH)_{3}(s) ⇌ Fe^{3+}(aq) + 3OH^{–}(aq) is decreased by 1/4 times, then equilibrium concentration of Fe^{3+} will be increased by**

- 64 times
- 4 times
- 8 times
- 16 times

**Answer:** 1. 64 times

**Question 25. The equilibrium constant (K _{p}) for the decomposition of gaseous H_{2}O, \(\mathrm{H}_2 \mathrm{O}(g) \rightleftharpoons \mathrm{H}_2(g)+\frac{1}{2} \mathrm{O}_2(g)\) is related to degree of dissociation (a ) at a total pressure (P) as-**

- \(\kappa_p=\frac{\alpha^3 p^{1 / 2}}{(1+\alpha)(2+\alpha)^{1 / 2}}\)
- \(K_p=\frac{\alpha^3 p^{3 / 2}}{(1-\alpha)(2+\alpha)^{1 / 2}}\)
- \(K_p=\frac{\alpha^{3 / 2} p^2}{(1-\alpha)(2+\alpha)^{1 / 2}}\)
- \(K_P=\frac{\alpha^{3 / 2} p^{1 / 2}}{(1-\alpha)(2+\alpha)^{1 / 2}}\)

**Answer:** 4. \(K_P=\frac{\alpha^{3 / 2} p^{1 / 2}}{(1-\alpha)(2+\alpha)^{1 / 2}}\)

**Question 26. 2 mol of PCl _{5}(g) is heated at a given temperature in a closed vessel of volume 2L. As a result, PCl_{5}(g) dissociates and forms PCl_{3}(g) and Cl_{2}(g). When the dissociation reaction reaches equilibrium, it Is found that 50% of PClg(g) has dissociated. Kc for the reaction is**

- 0.15
- 0.30
- 0.25
- 0.5

**Answer:** 4. 0.5

**Question 27. At a given temperature, the reaction, SO _{2}Cl_{2}(g) SO_{2}(g) + CI_{2}(g), is in a state of equilibrium in a closed vessel. At constant temperature and volume, if some amount of He gas is added to the reaction system, then —**

- The concentration of SO
_{2}(g) will increase - The concentration of SO
_{2}Cl_{2}(g) will increase - The concentrations of SO
_{2}(g) , Cl_{2}(g) , SO_{2}cl_{2}(g) will remain the same - The value of the equilibrium constant will decrease

**Answer:** 3. The concentrations of SO_{2}(g) , Cl_{2}(g) , SO_{2}cl_{2}(g) will remain the same

**Question 28. The reaction, C(s) + CO _{2}(g);⇌2CO(g), is in a state of equilibrium in a closed vessel at a constant temperature. The equilibrium of the reaction will shift towards the left and get re-established if at constant temperature and volume some amount of—**

- C(s) is removed from the reaction system
- CO
_{2}(g) is added to the reaction system - CO
_{2}(g) is removed from the reaction system - CO(g) is removed from the reaction system

**Answer:** 3. CO_{2}(g) is removed from the reaction system

**Question 29. The pair of compounds which cannot exist together in solution is**

- NaHCO
_{3}and NaOH - Na
_{2}CO_{3}and NaHCO_{3} - Na
_{2}CO3 and NaOH - NaHCO
_{3}and NaCl

**Answer:** 1. NaHCO_{3} and NaOH

**Question 30. Equimolar solutions of the following were prepared in water separately. Which of the solutions will have the highest pH**

- Srcl
_{2} - Bacl
_{2} - MgC
_{2} - Cacl
_{2}

**Answer:** 2. Bacl_{2}

**Question 31. A student wants to prepare a saturated solution of Ag ^{+} ion. He has only three samples of Ag— AgCl (K_{sp} = 1.8 × 10^{-18}), AgBr (K_{sp} = 5 × 10^{-13}), and Ag_{2}CrO_{4} (K_{sp} = 2.4 × 10^{-12}). Which compound should he take’ to obtain maximum [Ag^{+}] **

- Agcl
- AgBr
- Ag
_{2}CrO_{24} - None of these

**Answer:** 3. Ag_{2}CrO_{4}

**Question 32. The correct relationship between the pH of picomolar solutions of sodium oxide (pH _{2}), sodium sulfide (pH_{2}), sodium selenide (pH_{3}), and sodium telluride (pH_{4}) is**

- pH
_{1}>pH_{2}>pH_{3}>pH_{4} - pH
_{1}<pH_{2}<pH_{3}< pH_{4} - pH
_{1}<pH_{2}<pH_{3}<pH_{4} - pH
_{1}>pH_{2}=pH_{3}>pH_{4}

**Answer:** 1. pH_{1}>pH_{2}>pH_{3}>pH_{4}

**Question 33. Solubility product constant (K _{sp}) of salts of types MX_{1}, MX_{2} & M_{3}X at temperature K_{sp} are 4.0 × 10^{-8}, 3.2 ×10^{-14} & 2.7×10^{-13} respectively. Solubilities (mol dm^{-3}) of the salts at temperature T are in the order—**

- M
_{3}>MX_{2}>M_{3}X - M
_{3}X>MX_{2}>MX - MX
_{2}>M_{3}X>MX - MX>M
_{3}X>MX_{2}

**Answer:** 4. MX>M_{3}X>MX_{2}

**Question 34. If the solubilities of AgCl in H _{2}O,0.01(M) CaCl_{2} , 0.01(M) NaCl and 0.05(M) AgNO_{3} are S_{1}, S_{2}, S_{2} Ansd S_{2} respectively, then—**

- S
_{1}>S_{2}>S_{3}>S_{4} - S
_{1}> S_{2}= S_{3}> S_{4} - S
_{1}> s_{3}> S_{2}> S_{4} - S
_{4}>S_{2}>S_{3}>S_{1}

**Answer:** 3. S_{1} > s_{3} > S_{2} > S_{4}

**Question 35. The degree of hydrolysis of a salt of weak acid and weak base in its 0.01(M) solution is found to be 50%. If the molarity of the solution is 0.2(M), the percentage hydrolysis of the salt should be**

- 100%
- 50%
- 25%
- 10%

**Answer:** 2. 50%

**Question 36. The first and second dissociation constants of an acid H _{2}A are 1.0×10^{-5} and 5.0×10^{-10} respectively. The first and second dissociation constants of an **

- 5.0 ×10
^{-5} - 5.0 ×10
^{15} - 5.0 ×10
^{-15} - 0.2×10
^{5}

**Answer:** 3. 5.0 ×10^{-15}

**Question 37. If three salts P _{2}X, QY_{2}, and RZ_{3 }have the same solubilities in water then the correct relation among their Ksp values is—**

- \(K_{s p}\left(\mathrm{P}_2 \mathrm{X}\right)=K_{s p}\left(\mathrm{QY}_2\right)<K_{s p}\left(\mathrm{RZ}_3\right)\)
- \(K_{s p}\left(\mathrm{P}_2 \mathrm{X}\right)>K_{s p}\left(\mathrm{QY}_2\right)=K_{s p}\left(\mathrm{RZ}_3\right)\)
- \(K_{s p}\left(\mathrm{P}_2 \mathrm{X}\right)=K_{s p}\left(\mathrm{QY}_2\right)=K_{s p}\left(\mathrm{RZ}_3\right)\)
- \(K_{s p}\left(\mathrm{P}_2 \mathrm{X}\right)>K_{s p}\left(\mathrm{QY}_2\right)>K_{s p}\left(\mathrm{RZ}_3\right)\)

**Answer:** 1. \(K_{s p}\left(\mathrm{P}_2 \mathrm{X}\right)=K_{s p}\left(\mathrm{QY}_2\right)<K_{s p}\left(\mathrm{RZ}_3\right)\)

**Question 38. The pH of the solution was obtained by mixing 20 mL of ****0.01 (M) Ca(OH) _{2} and 30 of 0.1 (M) HCl solution is**

- 6.32
- 9.85
- 11.3
- 4.74

**Answer:** 3. 11.3

**Question 39. The pH of an aqueous solution of MCI is 3,0 and that of an aqueous solution of NaOH is 12. The pH of the solution obtained by mixing 100mL of NaOH solution with 500 ml, of HC1 solution’ is**

- 6.71
- 10.92
- 12.05
- 3.08

**Answer:** 2. 10.92

**Question 40. At 25°C, the pH of 0.1(M) aqueous solution of NH _{3} is 11.13. At the same temperature, the pH of a ‘solution containing 0.1 (M) of NH_{4}Cl and 0.01 (M) of NH_{3} is-**

- 4.74
- 6.25
- 8.26
- 9.34

**Answer:** 3. 8.26

**Question 41. 800ml. 0.1 (M) HCl solution is mixed with 200ml. 0.5(M) CH _{3}NH_{2} solution. In the resulting solution, traction of H_{3}O^{+} ions is = fix 10 is**

- 3×10
^{-5}(M) - 1.25 ×10
^{-4}(M) - 8×10
^{-11}(M) - 7.2×10
^{-10}(M)

**Answer:** 3. 8 × 10^{-11} (M)

**Question 42. A solution of a weak acid ( Kn = 10 ^{-5}) has a molarity of (M/5). lol of this solution is neutralized completely with a NaOH solution of molarity (M/20). At the neutra¬ lisation point, concentration of H(Of ions (mol-L^{-1} ) is**

- 4.39 × 10
^{-5} - 1.25 × 10
^{-6} - 7.02× 10
^{-8} - 1.58 × 10
^{-9}

**Answer:** 4. 1.58 × 10^{-9}

**Question 43. At 25°C, K for PbCI, is 1.6 × 10 ^{-5 }in water. At the same temperature, the amount of PbCl_{2} (molar mass = 278.19 g-mol^{-`1} ) that remains dissolved in 100 mL of a saturated solution of PbCL, is**

- 0.28g
- 0.44g
- 0.17g
- 0.35g

**Answer:** 2. 0.44g

**Question 44. At 25°C, the solubility product for Gd(OH) _{2} in water is 1.2 ×10^{-14 }What would be the pH of tut aqueous solution of 0.01 (M) Cd^{2+} ions when Cd(OH)_{2} starts precipitating**

- 4.29
- 5.60
- 8.04
- 7.56

**Answer:** 3. 8.04

**Question 45. At 25°C the solubility product of a salt AB0 in water is 4.0 × 10 ^{-15 }If 0.1 mol of A^{2-} ions are added to 1 1. of a saturated solution of the salt (assuming the volume of the solution does not change on the addition of A^{2-} ions), then**

- The solubility product of AB
_{2}will increase - The solubility product of AB
_{2 }will decrease - The cone, of b- ions in the solution will be 2 × 10
^{-7 }mol L^{-1} - The solubility of AB
_{2}in solution will be 4 × 10^{-10}. mol L^{-1}

**Answer:** 3. Cone, of b- ions in solution will be 2 ×10^{-7 }mol L^{-1 }

**Question 46. At 25°C, Kp for Al(OH) _{3}.( in water is 2 x 10-33 aqueous solution of ph = 13, the solubility of AI(OH)_{3} is 2 ×1 0^{-20 }. The value of x is**

- 10
- 15
- 22
- 30

**Answer:** 2. 15

**Question 47. At 25°C, K(l for a weak acid, HA in water, is 10- V _{2} ml. of 0.1 (M) NaOH solution is added to K, mL of 0.1 (M) solution of HA. How many times would Vl he of K, so that the pH of the solution is 6**

- 2 times
- 1.5 times
- 1.1 times
- 1.4 times

**Answer:** 3. 1.1 times

**Question 48. Which of the relations are correct for the given physical change; **

**⇒ \(\mathrm{CuSO}_4 \cdot 5 \mathrm{H}_2 \mathrm{O}(\mathrm{s}) \rightleftharpoons \mathrm{CuSO}_4 \cdot 3 \mathrm{H}_2 \mathrm{O}(\mathrm{s})+2 \mathrm{H}_2 \mathrm{O}(\mathrm{g})\) **

- \(K_p=p_{\mathrm{H}_2 \mathrm{O}}^2\)
- Kc = [H
_{2}O(g)]_{2} - Kp – K
_{c}(RT)_{2} - Kc = K
_{p}(RT)_{2}

**Answer:** 1. \(K_p=p_{\mathrm{H}_2 \mathrm{O}}^2\)

**Question 49. At a given temperature, Kc = 6.3 x 10-e for the reaction S-(g) 4S _{2}(g). At the same temperature, if the lead Ion is started with 2 moles of S0(g) and 0.2 mol of S_{2}(g) In a closed vessel of volume 1 L, then which of the following comments are true regarding this reaction—**

- At the beginning of the reaction, Q
_{p}= 8.0 × 10^{-4 } - The reaction will occur to a greater extent towards the right To attain equilibrium
- The reaction will occur to a greater extent towards the left to attain equilibrium
- The concentration of S
_{8}at equilibrium is greater than 2 mol. L^{-1 }

**Answer:** 1. At the beginning of the reaction, Q_{c} = 8.0 × 10^{-4 }

**Question 50. 4NH _{3}(g) + 5O_{2}(g)⇌4NO(g) + 6H_{2}O(g), is in equilibrlum In a closed container of volume 1L at a given temperature. If the reaction is started with 1 mol NH_{3}(g) and 1 mol of O_{2}(g) and the number of mol of H_{2}O(g) at equilibrium is 0.6 mol, then at equilibrium-**

- [NH
_{3}] = [NO] - [NO]<[O
_{2}] - [NO] > [NH
_{3}] - [O2] < [H
_{2}O]

**Answer:** 2. [NO]<[O_{2}]

**Question 51. The reaction, fe(s) + H _{2}O(g) ⇌ CO(g) + H_{2}(g); ΔH > 0, is in equilibrium. At equilibrium**

- If the temperature is increased, the partial pressure of H20(g) will decrease
- The concentration of H
_{2}(g) will decrease if an inert gas is added at constant temperature and volume - the concentration of CO(g) will increase if pressure is increased at a constant temperature
- The equilibrium will move towards the right if an inert gas is added at constant temperature and pressure.

**Answer:** 1. If the temperature is increased, the partial pressure of H_{2}O(g) will decrease

**Question 52. The reaction, 2NOCl(g)⇌ 2NO(g) + Cl _{2}(g) ; ΔH>0, Is In equilibrium. Winch of the following changes at equilibrium will decrease The yield of NO(g) —**

- At constant temperature and volume, some amount of nocl(g) is lidded to the reaction system u
- At constant temperature and volume, some amount of Cl
_{2}(f> ) is added to the reaction system - Temperature is decreased at equilibrium
- At constant temperature and pressure, some airfoil of the gas is added to the reaction system

**Answer:** 2. At constant temperature and volume, some amount of Cl_{2}(f> ) is added to the reaction system

**Question 53. The vapor density of the equilibrium mixture of NO _{2} and N_{2}O_{4} is found to be 40 for the given equilibrium N_{2}O_{4}(g) 2NO_{2}(g). For the given equilibrium**

- 1 Mole percent of nO
_{2}present in the mixture is 59% - 1 Mole percent of nO
_{2}present in the mixture is 26% - The degree of dissociation of n
_{2}O_{4}is 0.45 - The degree of dissociation of n
_{2}O_{4}is 0.15

**Answer:** 2. 1 Mole percent of nO_{2} present in the mixture is 26%

**Question 54. The vapor pressure of liquid methanol at 50°C is 55.5 kPa. These are correct for the equilibrium reaction attained in a closed vessel of 5 L at 50°C for the following equilibrium CH _{3}OH(Z) CH_{3}OH(g)**

- Kp = 55.5kPa
- Kc = 0.021 mol- L
^{-1 } - K = 0.555
- K = 0.555kPa

**Answer:** 1. Kp = 55.5kPa

**Question 55. The reactions in which the yield of the products cannot be increased by the application of high pressure are—**

- 2SO
_{2}(g) + O_{2}(g) ⇌2SO_{3}(g) - NH
_{4}HS(s)⇌ NH_{3}(g) + H_{2}S(g) - N
_{2}O_{4}(g)⇌2NO_{2}(g) - N
_{2}(g) + 3H_{2}(g)⇌2NH_{3}(g)

**Answer:** 2. NH_{4}HS(s) NH_{3}(g) + H_{2}S(g)

**Question 56. Aqueous solutions of which of the following compounds on dilution do not suffer any change in pH value—**

- PhCOONH
_{4} - NH
_{4}CN - HCOONa

**Answer:** 1. PhCOONH_{4}

**Question 57. Which can act as an acid as well as a base**

- SO
_{4}^{2-} - HS
^{–} - HCO
^{-3} - HSO
^{-4}

**Answer:** 2. HS^{–}

**Question 58. Which mixtures (in molar ratio) can act as buffer**

- H
_{2}CO_{3}+ NaOH (3:2) - H
_{2}CO_{3}+ NaOH (3: 4) - NH
_{3}+ HCl (5: 4) - NH
_{3}+ HCl (4: 5)

**Answer:** 1. H_{2}CO_{3} + NaOH (3:2)

**Question 59. If equal volumes of the given solutions are mixed, precipitation of AgCl (Ksp = 1.8 x 10-11) will occur only with**

- 10-4(M)Ag+ and 10-4(M)Cl
^{–} - 10-5(M)Ag+ and 10-5(M)Cl
^{–} - 10-6(M)Ag+ and 10-6(M)Cr
- 10-10(M)Ag+ and l0-10(M)Cl
^{–}

**Answer:** 1. 10-4(M)Ag+ and 10-4(M)Cl^{–}

**Question 60. Which ofthe following is true regarding H _{3}PO_{4}**

- Ka = Ka
_{1}X Ka_{2}X Ka_{3} - Ka
_{1}<Ka_{2}<Ka_{3} - ka
_{1}>ka_{2}> ka_{3} - ka
_{1}=ka_{2}=ka_{2}

**Answer:** 1. Ka = Ka_{1} X Ka_{2} X Ka_{3}

**Question 61. Select the buffer solutions-**

- 0.8(M) H
_{2}S+0.8(M)KHS - 2(M) C
_{6}H_{5}NH_{2}+2(M)C_{6}H_{5}NH_{3}Br - 3(M)H
_{2}Co_{3}+3(M)KHCO3 - 0.05(M) KClO
_{4}+0.05(M) HClO_{4}

**Answer:** 1. 0.8(M) H_{2}S+0.8(M)KHS

**Question 62. The solubility Of BaSO _{6} will be almost the same in**

- 0.1(M) H2O
_{4} - 0.1(M) Ba(OH)
_{2} - 0.1(M)BA(NO3)
_{2} - 0.2(M) HCl

**Answer:** 1. 0.1(M) H_{2}SO_{4}

**Question 63. The special that can act both and as Bronsted adds and as Bronsted base in water are-**

- H
_{2}PO_{2}-4 - PO
^{-3}_{4} - HCO
_{23} - [Fe(H
_{2}O)_{6}]^{3+}

**Answer:** 1. H_{2}PO_{2}

**Question 64. Among the following salts, whose aqueous solutions will turn blue litmus paper red-**

- NaHCO
_{3} - FeCl
_{3} - KCN
- C
_{6}H_{5}NH_{3}Cl

**Answer:** 2. NaHCO_{3}

**Question 65. At a given temperature, the first and the second ionization constants of the acid, H2A, are 10 × 10 ^{-5} and 5.0**

**× 10**r

^{-10 }**espectively. Which of the following comments are true regarding this add—**

- The concentration of A
^{2+}Ions In 0.01 (M) aqueous solution of H_{2}A Js 0,01 (Ml - The overall Ionisation constant for H
_{2}A is 5.0 ×10^{-15} - In 0,01 aqueous solution of H
_{2}A, the molar concentration of H30* Ions Is twice that of A^{2+}ions. - In 0,01 (M) aqueous solution of H
_{2}A, (H_{3}O+) × [HA-)

**Answer:** 2. The overall Ionisation constant for H_{2}A is 5.0 ×10^{-15}

**Question 66. At 25C, Kb for CN ^{–} (the conjugate base of HCN) is 2.5 × 10^{-5}, If 25rnf, of 0,01 (M) aqueous NaOH solution Is added to 50ml, of0,0 1 (M) HCN solution, then-**

- The pH of the solution is 1 1.2
- The pH of the respiting solution is 9.4
- At 20*c, the ionization constant for him is 4 × 10
^{-18} - At 23*c, the ionization constant for him is 2.5 × 10
^{-5}

**Answer:** 2. Ph of the respiting solution is 9.4

**Question 67. At a given temperature, If the solubility products for MX, MA _{2, }and M., B2 In the water are 10^{-22}, and 10^{-33} respectively and their solubilities are S_{1}, S_{2,} and S_{3} mol-1 respectively, then**

- S
_{1}<S_{3} - S
_{2}>S_{3} - S
_{2}>S_{1} - S
_{2}=S_{3}

**Answer:** 1. S_{1}<S_{3}

**Question 68. At 25-C temperature, the solubility products for BaCrO _{4} and SrCrO_{4} salts are 2,4 × 10^{10}**

**and 3.6 × 10**

^{-6}respectively. If an aqueous solution of K_{2}CrO_{4}is added drop by drop to an aqueous solution containing Ba^{2+}and Sr^{2}_{4 }ions with concentrations of 10^{-4}and 10^{-3}M) respectively, then—- BaCrO
_{4}will be precipitated first - SrCrO
_{4}will be precipitated first - The concentration of sr
^{2+}ions will be 6.6 × 10^{-8}mol-L^{-1}when ba^{2+}ions start precipitating - The concentration of ba
^{2+}ions will be 6.6 × 10^{-8}mol-L^{-1} - when sr
^{2+}ions start precipitating.

**Answer:** 1. BaCrO_{4} will be precipitated Erst

**Question 69. In a buffer solution composed of NaCN and HCN [pKa = 9.4), [NaCN] = 0.2(M) and [HCN] = 0.4(M). An aqueous solution contains Zn ^{2+}, Ca^{2+}, Mn^{2+}, and Cr^{3+} ions, each of which has a concentration of 0.1(M). If 500mL of the buffer solution is added to 500mL of this aqueous solution, then the ions that will precipitate in the resulting solution are**

- Zn
^{+} - Ca
^{2+} - Mn
^{2+} - Cr
^{3+}

**Answer:** 1. Zn^{+}

**Question 70. At 25°C, pKb(NH _{3}) = 4.74, pK_{a}(HF) = 3.14 and pK_{a}(HCN) = 9.4. Hence**

- An aqueous solution of nh
_{4}f is acidic - Aqueous solution of nh
_{4}cn is acidic - The pH of an aqueous solution of nh4cn is greater than that of an aqueous solution of nh4f
- Ph values of the solutions of both nh4cn and nh4f are independent of the concentrations ofthe solutions

**Answer:** 1. Aqueous solution of nh4f is acidic

**Question 71. Which of the following comments is true**

- If pK
_{a}values for the acids HA and HB are 4 and 5 respectively, then the concentration of OH- ions in 0.1(M) aqueous solution of HB will be greater than that in 0.1(M) aqueous solution of HA - pH of pure water at 0°C is smaller than that at 25°C
- The degree of hydrolysis of NH
_{4}F in its 0.1 (M) and 0.2(M) aqueous solutions is the same at a particular temperature - pH of an acid is 5, implying that the acid is weak.

**Answer:** 1. If pKa values for the acids HA and HB are 4 and 5 respectively, then the concentration of OH- ions in 0.1(M) aqueous solution ofHB will be greater than that in 0.1(M) aqueous solution of HA

**Question 72. A certain buffer solution contains equal concentrations of A- and HA. Kb for A- is 10-10. Hence**

- K
_{a}for HA is 10^{-3} - k
_{a}for HA is 10^{-4} - pH of the buffer is 4
- PH of the better is 9

**Answer:** 2. ka for HA is 10-4

**Question 73. A buffer solution containing NH3 and NHÿCl has a pH value of 9. pKb for NH3 is 4.7. If in the buffer solution, the total concentration of buffering reagents is 0.6 mol I.-1, then the amount of—**

- NH
_{3}in the solution is 3.4g.L^{-1} - NH
_{4}C1 in the solution is 8.9g.L^{-1} - NH
_{4}Cl in the solution is 21.4g.L^{-1} - NH
_{3}in the solution is 17.5g.L^{-1}

**Answer:** 1. NH_{3} in the solution is 3.4g.L^{-1}