If the equilibrium constant for the reaction $H_{2(g)}+I_{2(g)} \rightleftharpoons 2 HI_{(g)}$ is $K $ What is the equilibrium constant of $HI_{(g)} \rightleftharpoons \large\frac{1}{2} $$H_{2(g)}+\large\frac{1}{2} $$I_{2(g)}$?

Question

\[\begin {array} {1 1} (1)\;\frac{1}{K} & \quad (2)\;\sqrt K \\ (3)\;K & \quad (4)\;\frac{1}{\sqrt K} \end {array}\]