The rms velocity of hydrogen is $\sqrt{7}$ times the rms velocity nitrogen. $ u _{ H _{2}}=\sqrt{7} u _{ N _{2}} $ The rms velocity of a gas is directly proportional to square root of temperatue. $u \propto \sqrt{ T }$ $ \begin{array}{l} \sqrt{ T _{ H _{2}}}=\sqrt{7} \sqrt{ T _{ N 2}} \\ T _{ H _{2}}=7 T _{ N _{2}} \\ T _{ H _{2}}> T _{ N _{2}} \end{array} $