No link.

21. H₂, O₂, N₂, and He are enclosed in Identical containers under the similar conditions of pressure and temperature. The gases will have 

$$\begin{gathered} \left(a\right) same R.M.S speed \left(b\right) same \frac{K.E.}{kg} \\ \left(c\right) different \frac{K.E.}{mole} \left(d\right) same \frac{K.E.}{vol} \end{gathered}$$

Dear Student,

Equal volume of all gases under same temperature and pressure contains equal number of molecules. i.e., 1 unit volume of all gases contain equal number of molecules under same temperature and pressure.

Also, all gases at a given temperature have the same average kinetic energy. i.e., each molecule possess same energy (3kT/2) at a given temperature.

Therefore, under similar condition of temperature and pressure all gases will have same kinetic energy per unit volume (KE/vol.). Ans (d)

Regards,