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Equilibrium · Question 6

NEET (UG) 2025MCQEasy📈 Topic in 25% papers+4−1
1

Phosphoric acid ionizes in three steps with their ionization constant values Ka1, Ka2 and Ka3, respectively, while K is the overall ionization constant. Which of the following statements are true? Choose the correct answer from the options given below :

  1. B, C and D only
  2. A, B and C only
  3. A and B only
  4. A and C only

Answer

(2) A, B and C only

Solution

Overall ionisation: H3PO4 3H+ + PO43-

K = Ka1 Ka2 Ka3 (overall constant = product of the stepwise constants).

A. Taking logarithms: K = Ka1 + Ka2 + Ka3. True.

B. As per NCERT, it is easier to remove H+ from a neutral molecule than from a negatively charged ion, so H3PO4 is a stronger acid than H2PO4- and HPO42-. True.

C. For the same reason Ka1 > Ka2 > Ka3. True.

D. The stepwise constants are not related as Ka1 = Ka3 + Ka22; in fact Ka1 is much larger than both Ka2 and Ka3. False.

A, B and C only.

Answer: (2)

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2

Higher yield of NO in N2(g) + O2(g) 2NO(g) can be obtained at [ H of the reaction = +180.7 kJ mol-1] Choose the correct answer from the options given below :

  1. B, C, D only
  2. A, C, D only
  3. A, D only
  4. B, C only
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3

In which of the following equilibria, Kp and Kc are NOT equal?

  1. PCl5(g) PCl3(g) + Cl2(g)
  2. H2(g) + I2(g) 2HI(g)
  3. CO(g) + H2O(g) CO2(g) + H2(g)
  4. 2BrCl(g) Br2(g) + Cl2(g)
NEET (UG) 2024
4

For the reaction 2A B + C, Kc = 4 10-3. At a given time, the composition of reaction mixture is: [A] = [B] = [C] = 2 10-3 M. Then, which of the following is correct?

  1. Reaction is at equilibrium.
  2. Reaction has a tendency to go in forward direction.
  3. Reaction has a tendency to go in backward direction.
  4. Reaction has gone to completion in forward direction.
NEET (UG) 2024
5

Consider the following reaction in a sealed vessel at equilibrium with concentrations of N2 = 3.0 10-3 M, O2 = 4.2 10-3 M and NO = 2.8 10-3 M. 2NO(g) N2(g) + O2(g) If 0.1 mol L-1 of NO(g) is taken in a closed vessel, what will be degree of dissociation ( ) of NO(g) at equilibrium?

  1. 0.00889
  2. 0.0889
  3. 0.8889
  4. 0.717
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6

At a given temperature and pressure, the equilibrium constant values for the equilibria are given below: 3A2 + B2 2A3B, K1 A3B 32A2 + 12B2, K2 The relation between K1 and K2 is :

  1. K12 = 2K2
  2. K2 = K12
  3. K1 = 1 K2
  4. K2 = 1 K1
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7

For the reaction in equilibrium N2(g) + 3H2(g) 2NH3(g), H = -Q Reaction is favoured in forward direction by:

  1. use of catalyst
  2. decreasing concentration of N2
  3. low pressure, high temperature and high concentration of ammonia
  4. high pressure, low temperature and higher concentration of H2
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8

The ratio of solubility of AgCl in 0.1 M KCl solution to the solubility of AgCl in water is: (Given : Solubility product of AgCl = 10-10)

  1. 10-4
  2. 10-6
  3. 10-9
  4. 10-5
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9

Amongst the given options which of the following molecules/ion acts as a Lewis acid?

  1. H2O
  2. BF3
  3. OH-
  4. NH3
NEET (UG) 2023
10

The equilibrium concentrations of the species in the reaction A + B C + D are 2, 3, 10 and 6 mol L-1, respectively at 300 K. G for the reaction is (R = 2 cal/mol K)

  1. -137.26 cal
  2. -1381.80 cal
  3. -13.73 cal
  4. 1372.60 cal
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11

For the reaction N2(g) + 3H2(g) 2NH3(g), H = -92.4 kJ mol-1. The yield of ammonia increases on

  1. increasing temperature
  2. decreasing pressure
  3. increasing pressure
  4. adding a catalyst
NEET (UG) 2022

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