Question

$2.8$ litre of a gas at STP have $4$ grams weight than gas may be:

• A. ${CO}_2$
• B. ${NO}_2$
• C. $CO$
• D. $O_2$

Answer 1

The correct option is D $O_2$

At STP 22.4 L of any gas=Molecular mass of the gas=1 mole of gas

2.8 L Volume of gas at STP=4 g

1 L Volume of gas STP$=\frac{4}{2.8}$ g

22.4 L Volume of gas at STP$=\frac{4\times 22.4}{2.8}=32$ g

32 g is the molecular mass of $O_2$