The values of $K_{P 1}$ and $K_{\mathrm{P} 2}$ for the reactions $$ \begin{aligned} & X \rightleftharpoons Y+Z . \\ & A \rightleftharpoons 2 B . . \end{aligned} $$ are in ratio of 9:1. If degree of dissociation of $X$ and $\mathrm{A}$ be equal, then total pressure at equilibrium (1) and (2) are in the ratio

• A

  $1: 1$
• B

  $3: 1$
• C

  $1: 9$
• Correct answer
  D

  $36: 1$

Solution

$$ \begin{aligned} & \text { or } \frac{\mathrm{K}_{\mathrm{P}_1}}{\mathrm{~K}_{\mathrm{P}_2}}=\frac{\mathrm{P}}{4 \mathrm{P}^{\prime}} \quad \text { or } \quad \frac{9}{1}=\frac{\mathrm{P}}{4 \mathrm{P}^{\prime}} \\ & \text { or } \frac{\mathrm{P}^{\prime}}{\mathrm{P}}=36: 1 \end{aligned} $$

Hence, the correct answer is option: 'D'.