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Equilibrium · Question 36

JEE Main 2025 (Online) 2nd April Morning ShiftMCQMedium📈 Topic in 16% papers+4−1
1

If equal volumes of AB2 and XY (both are salts) aqueous solutions are mixed, which of the following combination will give a precipitate of AY2 at 300 K ? (Given Ksp (at 300 K) for AY2 = 5.2 10-7)

  1. 2.0 10-4 M AB2, 0.8 10-3 M XY
  2. 2.0 10-2 M AB2, 2.0 10-2 M XY
  3. 1.5 10-4 M AB2, 1.5 10-3 M XY
  4. 3.6 10-3 M AB2, 5.0 10-4 M XY

Answer

(2) 2.0 10-2 M AB2, 2.0 10-2 M XY

Solution

On mixing equal volumes, each concentration is halved.

AB2 A2+ + 2B- and XY X+ + Y-

Precipitation of AY2 occurs when ionic product Q = [A2+][Y-]2 > Ksp = 5.2 10-7

(1) Q = (1.0 10-4)(0.4 10-3)2 = 1.6 10-11 < Ksp

(2) Q = (1.0 10-2)(1.0 10-2)2 = 1.0 10-6 > Ksp precipitate forms

(3) Q = (0.75 10-4)(0.75 10-3)2 4.2 10-11 < Ksp

(4) Q = (1.8 10-3)(2.5 10-4)2 1.1 10-10 < Ksp

Answer: (2)

JEE Main 2025 (Online) 2nd April Morning Shift

Keep practising — Equilibrium

2

Consider the following equilibrium, CO(g) + 2H2(g) CH3OH(g) 0.1 mol of CO along with a catalyst is present in a 2 dm3 flask maintained at 500 K. Hydrogen is introduced into the flask until the pressure is 5 bar and 0.04 mol of CH3OH is formed. The Kp is 10-3 (nearest integer). Given : R = 0.08 dm3 bar K-1 mol-1 Assume only methanol is formed as the product and the system follows ideal gas behaviour.

JEE Main 2025 (Online) 2nd April Morning Shift
3

Consider the following chemical equilibrium of the gas phase reaction at a constant temperature : A(g) B(g) + C(g) If p is the total pressure, Kp is the pressure equilibrium constant and is the degree of dissociation, then which of the following is true at equilibrium?

  1. If Kp value is extremely high compared to p, becomes much less than unity
  2. When p increases, increases
  3. If p value is extremely high compared to Kp, 1
  4. When p increases, decreases
JEE Main 2025 (Online) 2nd April Evening Shift
4

At temperature T, compound AB2(g) dissociates as AB2(g) AB(g) + 12B2(g) having degree of dissociation x (small compared to unity). The correct expression for x in terms of Kp and p is:

  1. Kp
  2. [3] 2Kp2p
  3. [3] 2Kpp
  4. [4] 2Kpp
JEE Main 2025 (Online) 29th January Morning Shift
5

A weak acid HA has degree of dissociation x. Which option gives the correct expression of (pH - pKa)?

  1. ( 1-xx )
  2. 0
  3. (1+2x)
  4. ( x1-x )
JEE Main 2025 (Online) 28th January Morning Shift
6

Ice and water are placed in a closed container at a pressure of 1 atm and temperature 273.15 K. If pressure of the system is increased 2 times, keeping temperature constant, then identify correct observation from following

  1. Liquid phase disappears completely.
  2. The amount of ice decreases.
  3. The solid phase (ice) disappears completely.
  4. Volume of system increases.
JEE Main 2025 (Online) 28th January Morning Shift
7

Arrange the following in increasing order of solubility product : Ca(OH)2, AgBr, PbS, HgS

  1. PbS < HgS < Ca(OH)2 < AgBr
  2. HgS < AgBr < PbS < Ca(OH)2
  3. HgS < PbS < AgBr < Ca(OH)2
  4. Ca(OH)2 < AgBr < HgS < PbS
JEE Main 2025 (Online) 28th January Evening Shift

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