2.8 g of a gas at 1 atm and 273K occupies a volume of 2.24 litres, the gas can not be:

Let the molar mass of the gas be M gm/moleApplying Ideal gas equation to given situationPV=nRT 1×2.24=2.8M×0.0821×273M = 28 gm/moleSo, the gas can't be Oxygen because its molar mass is 32 gm/moleHence, Option "A" is the correct answer