Question

The degree of dissociation of $PC{l}_5\left(g\right)\rightleftharpoons PC{l}_3\left(g\right)+C{l}_2\left(g\right)$, ___________ with increase in pressure at equilibrium.

• A. increases
• B. decreases
• C. first increases and then decreases
• D. first decreases and then increases

Answer 1

The correct option is B decreases

With an increase in the pressure, the equilibrium will shift in the direction in which there is decrease in the number of moles so as to nullify the effect of increased pressure. The number of moles of the reactant is less than the total number of moles of the product. Hence, the equilibrium will shift in the backward direction. This will suppress the dissociation.