Question

$2.8\text{g}$ of a gas at $1\text{atm}$ and $273\text{K}$ occupies a volume of 2.24 litres. The gas cannot be:

• A. $O_2$
• B. $CO$
• C. $N_2$
• D. $C_2{H}_4$

Answer 1

The correct option is A $O_2$

If the gas occupies $2.24\text{L}$ at STP it means 0.1 mole is present.
0.1 mole of a gas has a mass of $2.8\text{g}$
1 mole will have a mass of $28\text{g}$
So, we can say that the molar mass of the gas is $28\text{g/mol}$
Molar mass of $O_2=32\text{g/mol}$
The other gases have a molar mass of 28 g/mol.