Same gas is filled in two vessels of the same volume at the same...

The rms velocity of a gas is given by ${V}_{rms} = \sqrt{\dfrac{3RT}{M}}$. Therefore,${V}_{rms}$ is independent of number of moles, Hence, statement A is correct and D is incorrect.

According to the ideal gas equation $PV = nRT ⇒ P ∝ n$

$⇒ \dfrac{{P}_{1}}{{P}_{2}} = \dfrac{{n}_{1}}{{n}_{2}} = \dfrac{1}{4}$

Hence, statement B is correct and C is incorrect.

Ans [$A \text{ and } B$ only are correct]