Question

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?

• A. Reaction is at equilibrium.
• B. Reaction has a tendency to go in forward direction.
• C. Reaction has a tendency to go in backward direction.
• D. Reaction has gone to completion in forward direction.

Answer 1

Answer: (C)

Reaction has a tendency to go in backward direction.

Answer 2

The reaction quotient $Q_c$ is calculated as:
$Q_c = \frac{[B][C]}{[A]^2} = \frac{(2 \times 10^{-3})(2 \times 10^{-3})}{(2 \times 10^{-3})^2} = 1$.
Since $Q_c > K_c$, the reaction will shift in the backward direction to establish equilibrium.