Question

In the reaction $R\left(g\right)\rightleftharpoons P\left(g\right)$
In which of the following conditions the reaction will move towards backward direction to attain equilibrium?
Here $Q_c$ is the reaction quotient at a given time t and $K_c$ is the equilibrium contsnt

• A. $Q_c>K_c$
• B. $Q_c<K_c$
• C. $Q_c=K_c$
• D. None of the above

Answer 1

The correct option is A $Q_c>K_c$

For the reaction $R\left(g\right)\rightleftharpoons P\left(g\right)$ , reaction quotient at a given time is represented by
$Q_c=\frac{[P{]}_t}{[R{]}_t}$
and equilibrium constant $K_c$

$K_c=\frac{[P{]}_{eq}}{[R{]}_{eq}}$
When $Q_c>K_c$, the amount of products at a given time is greater than the equilibrium conentration of products. So, for the equilibrium condition to be attained, the reaction has to move backward, and thus when $K_c=Q_c$ the, equilibrium will be attained.