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