Equilibrium pressure $=2.46\, atm$

$PCl _{5}( g ) \rightleftharpoons PCl _{3}( g )+ C \ell_{2}( g )$

$t =0 \quad\quad\quad 5 \quad\quad\quad\quad 0\quad\quad 0$

$t = Eq ^{ m }\quad\quad 5- x\quad\,\,\,\, x \quad\quad x$

from ideal gas equation

$PV = nRT$

$2.46 \times 200=(5-x+x+x+2) \times 0.082 \times 600$ $x =3$

$K _{ P }=\frac{ n _{ PCl _{3}} \times n _{ Cl _{2}}}{ n _{ PCl _{5}}} \times\left[\frac{ P _{\text {totall }}}{ n _{\text {total }}}\right]$

$\frac{3 \times 3}{2} \times \frac{2.46}{10}=1.107=1107 \times 10^{-3}$