At what temperature (in K ) the rms velocity of $\mathrm{SO}_2$ molecules is equal to rms velocity of $\mathrm{O}_2$ molecules at $27^{\circ} \mathrm{C}$ ?

For one mole of an ideal gas an isochore is obtained. The slope of the isochore is $0.082 \mathrm{~atm} \mathrm{~K}^{-1}$. What will be its pressure (in atm) when the temperature is $12.2 \mathrm{~K} ?\left(R=0.082 \mathrm{~L} \mathrm{~atm} \mathrm{~mol}^{-1} \mathrm{~K}^{-1}\right)$

At $\mathrm{T}(\mathrm{K})$, a gaseous mixture contains $\mathrm{H}_2$ and $\mathrm{O}_2$. The total pressure of the mixture is 2 bar. The partial pressure of $\mathrm{H}_2$ is 1.778 bar. What is the weight $(w / w)$ percentage of $\mathrm{H}_2$ in the mixture?