At temperature T, compound AB_2( g ) dissociates as AB_2( g ) ⇌ AB_( g ) +1/2 B_2( g ) having degree of dissociation x (small compared to unity). The…

At temperature T, compound $\displaystyle \mathrm{AB}_{2(\mathrm{~g})}$ dissociates as $\displaystyle \mathrm{AB}_{2(\mathrm{~g})} \rightleftharpoons \mathrm{AB}_{(\mathrm{g})}+\frac{1}{2} \mathrm{~B}_{2(\mathrm{~g})}$ having degree of dissociation $\displaystyle x$ (small compared to unity). The correct expression for $\displaystyle x$ in terms of $\displaystyle \mathrm{K}_{\mathrm{p}}$ and p is