Gas at a pressure P0 is contained in a vessel masses of all the molecules are halved and their speeds are doubled, the resulting pressure ‘P’ will be equal to

root mean square velocity of molecules of gas is Vrms=3PVmhere P is pressure;V is volume; m=mass of gasV1V2=P1P2×m2m1given V2=2V1;m2=m2; P1=P0  ;substitute in above equation V12V1=P0P2×m2m12=P0P2×1214=P0P2×12P2=2P0