Question

For the reaction, $PC{l}_5\left(g\right)\rightleftharpoons PC{l}_3\left(g\right)+C{l}_2\left(g\right)$, the degree of dissociation 'x' is related to pressure 'P

• A.
• B.
• C.
• D.

Answer 1

The correct option is B

\begin{array}{c c c}

\text{} & \text{PCl_5(g)} & \text{$\rightleftharpoons$} & \text{$PC{l}_3\left(g\right)$} & \text{+} & \text{$PC{l}_3\left(g\right)$}\\

\text{ $Ini.moles$} & \text{1} & \text{} & \text{0} & \text{} & \text{0} \\

\text{ eq.moles} & \text{(1-x)} & \text{} & \text{x} & \text{} & \text{x=(1+x)} \\

\end{array}

total number of eq.moles =$(1-x)+x+x=(1+x)$

eq.Pressure = P

$P_{PC{l}_5}=\frac{(1-x)}{(1+x)}\times P;P_{PC{l}_5}=\frac{x}{(1+x)}\times P;P_{C{l}_2}=\frac{x}{(1+x)}\times P$

$K=\frac{P_{PC{I}_5}\times P_{C{l}_2}}{P_{PC{l}_5}}=\frac{(\frac{x}{(1+x)}\times P)(\frac{x}{(1+x)}\times P)}{(\frac{(1+x)}{(1+x)}\times P)}=\frac{x^2.P}{(1-x^2)}$

$ifx<<1then(1-x^2)\approx 1);K=x^2.P;P\alpha \frac{1}{x^2}$