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Equilibrium · Question 34

JEE Main 2025 (Online) 3rd April Morning ShiftMCQMedium📈 Topic in 3% papers+4−1
1

In the following system, PCl5(g) PCl3(g) + Cl2(g) at equilibrium, upon addition of xenon gas at constant T & p, the concentration of

  1. PCl5, PCl3 & Cl2 remain constant
  2. PCl3 will increase
  3. Cl2 will decrease
  4. PCl5 will increase

Answer

(2) PCl3 will increase

Solution

Xenon is an inert gas. At constant T and p, adding it increases the total volume of the mixture.

Partial pressure of each reacting gas falls: pi = xi p and every mole fraction xi decreases.

Qp = pPCl3 pCl2pPCl5 = nPCl3 nCl2nPCl5 pntotal

ntotal increases Qp < Kp

By Le Chatelier's principle the equilibrium shifts in the forward direction, towards more gaseous moles ( ng = +1).

More PCl5 dissociates; PCl3 (and Cl2) are formed, so PCl3 will increase.

Answer: (2)

JEE Main 2025 (Online) 3rd April Morning Shift

Keep practising — Equilibrium

2

Given below are two statements : In the light of the above statements, choose the correct answer from the options given below

  1. Statement I is true but Statement II is false
  2. Statement I is false but Statement II is true
  3. Both Statement I and Statement II are true
  4. Both Statement I and Statement II are false
JEE Main 2025 (Online) 3rd April Morning Shift
3

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
JEE Main 2025 (Online) 2nd April Morning Shift
4

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
5

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
6

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
7

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
8

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
9

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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