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Equilibrium · Question 37

JEE Main 2025 (Online) 2nd April Morning ShiftNumericalMedium📈 Topic in 19% papers+4
1

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.

Answer

74

Solution

Total moles at equilibrium:

ntotal = PVRT = 5 20.08 500 = 0.25 mol

CO left = 0.1 - 0.04 = 0.06 mol; CH3OH = 0.04 mol

H2 at equilibrium = 0.25 - 0.06 - 0.04 = 0.15 mol

Partial pressure pi = nintotal P = ni 20 bar

pCO = 1.2 bar, pH2 = 3 bar, pCH3OH = 0.8 bar

Kp = pCH3OHpCO pH22 (pressures in bar, standard pressure 1 bar)

= 0.81.2 32 = 0.810.8

= 0.0741 74 10-3

Answer: 74

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Keep practising — Equilibrium

2

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
3

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
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4

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 )
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5

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.
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6

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
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