Question

At STP Which has greater volume 1g of H2 or 1g of He

Answer 1

1 g of Hydrogen Gas (H2) = 0.5 mole of Hydrogen gas since 2 gm. is the molar mass of Dihydrogen! Now by Avogadro's Law, 1 mole of any gas at STP would occupy 22.7 litres of volume.

So the volume He occupies is 11.2 Litre.

Therefore H2 is greter in volume