1 mole of any substance contains 6.02 x 10^23 particles.
Hence 0.25 mole of any has will contain 0.25 x 6.02 x 10^23 molecules of that gas
They cannot contain the same no. of atoms as 1 molecule of CO2 contains 3 atoms, 1 molecule H2 contains 2 molecules, and 1 molecule of NH3 contain 4 atoms
1 molecule of any gas will occupy 22.4 L at STP
hence 0.25 mol of all of these gases accupy the same volume
all of these molecules have different molar masses. thus their g.f.w cannot be same
Your answer is that they will occupy the same volume, and the same number of molecules