Tiêu đề Chemical Equilibrium 01.pdf ✅

1 JEE ADVANCED 2024 Chemical Equilibrium Single Correct (1 – 5) 1. The complexion of Fe2 + with the chelating agent dipyridyl has been studied kinetically in both the forward and reverse directions. Fe2 + + 3 dipy ⇌ [Fe(dipy)3 ] 2 + For this reaction, the rates of forward and reverse reactions are (1.45 × 1013M−3 s −1 )[Fe2 + ][ dipy ] 3 and (1.22 × 10−4 s −1 )[Fe(dipy) 3 2 + ] , at 25∘C . What is the stability constant of the complex? (1) 1.77 × 109 (2) 8.4 × 10−18 (3) 1.18 × 1017 (4) 5.65 × 10−10 2. For the reaction H2(g) + I2(g) ⇌ 2HI(g), the rate law expression is (1) − 1 2 ⋅ d[HI] dt = K −1 [HI] 2 − K 1 [H2 ][I2 ] (2) − 1 2 ⋅ d[HI] dt = K 1 [HI] 2 K−1[H2 ][I2 ] (3) − 1 2 ⋅ d[HI] dt = K 1 [H2 ][I2 ] − K −1 [HI] 2 (4) − 1 2 ⋅ d[HI] dt = K 1K −1 [H2 ][I2 ] 3. In the reaction N2 ( g) + 3H2 ( g) ⇌ 2NH3 ( g) + Heat. One mole of N2 reacts with three moles of H2. If at equilibrium ' x ' moles of N2 combined, then the value of ' x ' in terms of KP and the total pressure of gases at equilibrium P is (x ≪ 1) (1) 3P⋅√3⋅KP 8 (2) 8P 3√3⋅KP (3) 3√3⋅Kp 8P (4) 8 P ⋅ √ KP 3 4. Two moles of an equimolar mixture of two alcohols R1 − OH and R2 − OH are esterified with one mole of acetic acid. If only 80% of the acid is consumed till equilibrium and the quantities of ester formed under equilibrium are in the ratio 3: 2. What is the value of equilibrium constant for the esterification of R1 − OH? (1) 0.48 (2) 2.2 (3) 0.32 (4) 3.69 5. For the equilibrium A(g) ⇌ nB(g), the equilibrium constant KP is related with the degree of dissociation α, and the total pressure of gases at equilibrium P is (1) (nα) n⋅P n−1 (1−α)⋅[1 + (n−1)α] n−1 (2) (nα) n−1 ⋅P n−1 (1−α)⋅[1 + (n−1)α] n−1 (3) α n−1 ⋅P n−1 (1−α)⋅[1 + (n−1)α] (4) nα⋅P n−1 (1−α) n−1⋅[1 + (n−1)α] 6. The reaction A(g) + B(g) ⇌ C(g) + D(g) occurs in a single step. The rate constant of forward reaction is 2.0 × 10−3 mol−1 L s −1 . When the reaction is started with equimolar amounts of A and B, it is found that the concentration of A is twice that of C at equilibrium. The rate constant of the backward reaction is (1) 5.0 × 10−4 mol−1 L s −1 (2) 8.0 × 10−3 mol−1 L s −1 (3) 1.25 × 102 mol−1 L s −1 (4) 2.0 × 103 mol−1 L s −1 7. In an evacuated rigid vessel of volume V litre, one mole of solid ammonium carbonate (NH3)2CO2 is taken and the vessel is heated to T K . The equilibrium total pressure of gases is found to be P atm. The percentage dissociation of solid into NH3(g) and CO2(g) is (1) 100RT 3PV % (2) RT 3PV % (3) 100PV 3RT % (4) 300PV RT % DPP - 01
2 8. Suppose the gas phase isomerization reactions: A ⇌ B, A ⇌ C and B ⇌ C achieve equilibrium simultaneously at a fixed temperature. The equilibrium mole fraction of 'A' in terms of equilibrium constants, K1,K2 and K3 (respectively) is (1) K1 K1 + K2 + K3 (2) 1 1 + K1 + K2 (3) 1 K1 + K2 + K3 (4) 1 K1 + K2 9. For a reversible reaction A ⇌ K1 K1 B, the initial molar concentration of A and B are aM and b M , respectively. If xM of A is reacted till the achievement of equilibrium, then x is (1) K1a−K2b K1 + K2 (2) K1a−K2b K1−K2 (3) K1a−K2b K1K2 (4) K1a + K2b K1 + K2 10. PCl5 (molecular mass = M) dissociates into PCl3 and Cl2 as PCl5(g) ⇌ PCl3(g) + Cl2 (g). If the total pressure of the system at equilibrium is P and the density is ' d ' at temperature T K. The degree of dissociation of PCl5 may be represented as (1) PM dRT (2) PM dRT − 1 (3) dRT PM − 1 (4) dRT PM One or more than one correct 11. When NH4HS(s) is vaporized in an empty vessel and maintained at 20∘C , the equilibrium is established NH4HS(s) ⇌ NH3(g) + H2 S(g) and the total pressure of gases at equilibrium is 0.4 atm . When NH4HS(s) is vaporized in the presence of NH3(g) in the same vessel at 20∘C, the partial pressure of NH3(g) at equilibrium is 0.5 atm . Which of the following is/are correct statement(s)? (1) At second equilibrium, the final partial pressure of H2 S(g) is 0.08 atm. (2) In second experiment, the initial pressure of NH3(g) was 0.42 atm. (3) In the presence of NH3(g) , the extent of dissociation of NH4HS(s) is decreased. (4) At second equilibrium, the mole fraction of H2S(g) is 0.5. 12. Which of the following reaction(s) have KP = KC? (1) H2 (g) + I2 (g) ⇌ 2HI(g) (2) N2 (g) + O2 ( g) ⇌ 2NO(g) (3) 2NO(g) + Cl2 ( g) ⇌ 2NOCl(g) (4) 2SO2(g) + O2(g) ⇌ 2SO3(g) 13. A chemical system is in equilibrium. Addition of a catalyst would result in (1) increase in the rate of forward reaction. (2) increase in the rate of reverse reaction. (3) a new reaction pathway to reaction. (4) increase the amount of heat evolved. 14. A cylinder fitted with a movable piston contains liquid water in equilibrium with water vapour at 25oC. Which operation results in a decrease in the equilibrium vapour pressure? (1) Moving the piston downwards a short distance. (2) Removing a small amount of vapour. (3) Removing a small amount of the liquid water. (4) Dissolving salt in the water. Comprehension – 1 An amount of 0.20 moles of CO taken in a 2.463 L flask is maintained at 750 K along with a catalyst so that the following reaction can take place CO(g) + 2H2(g) ⇌ CH3OH(g). Hydrogen is introduced until the total pressure of the system is 7.5 atm at equilibrium and 0.1 mole of methanol is formed. 15. For the reaction, KP is (1) 0.16 atm–2 (2) 6.25 atm–2 (3) 0.04 atm–2 (4) 1.56 atm–2 16. For the reaction, KC is [Given: (2.463)2 = 6.07] (1) 6.07 M–2 (2) 607 M–2 (3) 151.75 M–2 (4) 2428 M–2 17. What is the final pressure if the same amount of CO and H2 as before used, but with no catalyst so that the reaction does not take place? (1) 18.75 atm (2) 10.0 atm (3) 15.0 atm (4) 12.5 atm
3 Integer Type Questions – Single Digit (0–9) 18. The percent dissociation of H2 S(g) if 0.1 mole of H2 S is kept in 0.4 L vessel at 1000 K for the reaction 2H2 S(g) ⇌ 2H2(g) + S2(g);KC = 1.0 × 10−6 . 19. COF2(g) passed over catalyst at 1000∘C comes to equilibrium 2COF2(g) ⇌ CO2(g) + CF4(g) . Analysis of the equilibrium mixture (after quick cooling to freeze the equilibrium) shows that 500 ml of the equilibrium mixture (STP) contains 300 ml (STP) of (COF2 + CO2) taking the total pressure to be 10 atm. The value of KP for the reaction is 20. The dissociation constant of PCl5 is 8 atm at 273oC. What pressure (in atm) will be developed when 62.55 g of this substance is vaporized at 273°C in 4480 ml vessel originally full of chlorine gas at 0oC and 1 atm pressure? 21. A mixture of equimolar quantities of ethyl alcohol and acetic acid is prepared. Immediately after mixing, 10 ml of mixture was neutralized by 10 ml of N-NaOH. When the mixture reaches the equilibrium, 10 ml requires 5 ml of N-NaOH for neutralization. What is the equilibrium constant for the formation of ester? 22. The degree of dissociation of HI at a particular temperature of 0.8. Calculate the volume (in litre) of 1.6 M-Na2S2O3 solution required to neutralize the iodine present in an equilibrium mixture of a reaction when 2 moles each of H2 and I2 are heated in a closed vessel of 2 L capacity Matrix – Match Type Questions 23. Match the columns. Column I Column II (A) Q = Keq (P) Reaction is near to completion. (B) Q < Keq (Q) Reaction is not at equilibrium. (C) Q > Keq (R) Reaction is fast in forward direction. (D) Keq ≫ > 1 (S) Reaction at equilibrium. (1) A→P, S; B→Q, R; C→Q, R; D→Q, R (2) A→S; B→Q, R; C→Q, P; D→Q, S (3) A→P, S; B→Q, S; C→Q, P; D→Q, R (4) A→P, R; B→Q, P; C→Q, S; D→Q, R
4 Answer Key 1 . ( 3 ) 2 . ( 1 ) 3 . ( 1 ) 4 . ( 2 ) 5 . ( 1 ) 6 . ( 2 ) 7 . ( 3 ) 8 . ( 2 ) 9 . ( 1 ) 10 . ( 2 ) 11 . (1, 2 , 3 ) 12 . (1, 2 ) 13 . ( 3 ) 14 . ( 4 ) 1 5 . (1) 1 6 . (2) 17 . ( 2 ) 18 . ( 0 1 ) 19 . (04 ) 20 . (10 ) 2 1 . (01 ) 2 2 . ( 0 8 ) 2 3 . ( 2 )