Question

$2$ mole each of $P{Cl}_3$ and ${Cl}_2$ and $1$ mole of $P{Cl}_3$ are taken in $5$ lt. flask at ${27}^{o}C$. After following equilibrium is attained in gaseous phase, $P{Cl}_5\rightleftharpoons P{Cl}_3+{Cl}_2$. $P{Cl}_5$ is found to be $40$% dissociated. Calculate equilibrium constant $K_C$.

Answer 1

${PCl}_5\rightleftharpoons {PCl}_3+{Cl}_{2}T={27}^{0}CV=5lit$

At $t=0$ $1$ $2$ $2$

$\Delta t$ $t=t_{eq}$ $1-\alpha$ $2+\alpha$ $2+\alpha$

$\alpha$ is given as $O.H$ ($\because 40$% dissociated)

concentration of ${PCl}_5=\frac{0.6}{5}=0.12$

concentration of ${PCl}_3=\frac{2.4}{5}=0.48$

concentration of ${Cl}_2=\frac{2.4}{5}=0.48$

$K_C=\frac{\left(0.48\right)\left(0.48\right)}{0.12}$

$=1.92$