Question

Consider the following reactions in equilibrium with initial concentration of 0.01 M of every species (assuming the same equilibrium constant same).
(I)$PC{l}_5\left(g\right)\rightleftharpoons PC{l}_3\left(g\right)+C{l}_2\left(g\right)$
(II)$2HI\left(g\right)\rightleftharpoons H_2\left(g\right)+I_2\left(g\right)$
(III)$N_2\left(g\right)+3H_2\left(g\right)\rightleftharpoons 2N{H}_3\left(g\right)$
Arrange these reactions in the order of the extent to which it takes place.

• A. I > II > III
• B. I < II < III
• C. II < III< I
• D. III < I < II

Answer 1

The correct option is B I < II < III

On going from the reactions (i), (ii) and (iii), the product of the concentrations of reactants raised to appropriate powers decreases. But the value of the equilibrium constant is same. Hence, the product of the concentrations of products raised to appropriate powers increases. Hence, the extent of the reaction increases in the order I < II < III.