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Equilibrium · Question 1

NEET (UG) 2026MCQEasy📈 Topic in 25% papers+4−1
1

At 298 K, a certain buffer solution contains equal concentrations of X- and HX. Kb for X- is 10-10. What is the pH of this buffer solution?

  1. 10
  2. 4
  3. 2
  4. 6

Answer

(2) 4

Solution

Ka(HX) = KwKb(X-) = 10-1410-10 = 10-4

⇒ pKa = 4

For an acidic buffer (Henderson equation): pH = pKa + log [X-][HX]

∵ [X-] = [HX] ⇒ pH = 4 + log 1 = 4

Answer: (2)

NEET (UG) 2026

Keep practising — Equilibrium

2

Given below are certain reactions. Identify the reaction for which Kp Kc.

  1. N2(g) + O2(g) 2NO(g)
  2. H2O(g) + CO(g) H2(g) + CO2(g)
  3. N2(g) + 3H2(g) 2NH3(g)
  4. H2(g) + I2(g) 2HI(g)
NEET (UG) 2026
3

In a qualitative analysis, Bi3+ is detected by appearance of precipitate of BiO(OH)(s). Calculate pH when the following equilibrium exists at 298 K : BiO(OH)(s) BiO+(aq) + OH-(aq), K = 4 × 10-10 (Given : log 2 = 0.3010)

  1. 4.699
  2. 5.286
  3. 8.714
  4. 9.301
NEET (UG) 2026
4

The correct order of solubility of the given salts in water at 298 K is array|l|l| Salt & Ksp at 298 K \ AgBr & 5.0 10-13 \ Zn(OH)2 & 1.0 10-15 \ Hg2Cl2 & 1.3 10-18 \ array

  1. Zn(OH)2 > AgBr > Hg2Cl2
  2. Hg2Cl2 > Zn(OH)2 > AgBr
  3. AgBr > Zn(OH)2 > Hg2Cl2
  4. Hg2Cl2 > AgBr > Zn(OH)2
RE-NEET (UG) 2026
5

For the reaction A(g) 2B(g), the backward reaction rate constant is higher than the forward reaction rate constant by a factor of 2500, at 1000 K. [Given : R = 0.0831 L atm mol-1 K-1] Kp for the reaction at 1000 K is

  1. 0.033
  2. 0.021
  3. 83.1
  4. 2.077 105
NEET (UG) 2025
6

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
NEET (UG) 2025
7

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
NEET (UG) 2025
8

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
9

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
10

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
NEET (UG) 2024
11

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
RE-NEET (UG) 2024

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