Question

What volume of air at STP containing 30% of oxygen by volume is required to completely form 1000 g of sulphur containing 4% incombustible matter?

• A. 2720 L
• B. 1800 L
• C. 2270 L
• D. 3600 L

Answer 1

The correct option is C 2270 L

The balanced chemical equation is:
$S+O_2⟶S{O}_2$
1 mol 1 mol
32 g 22.4 L

Amount of sulphur in the sample,
= $\frac{1000\times 96}{100}=960g$
32 g of sulphur requires 22.7 L of oxygen at STP.
960 g of sulphur requires = $\frac{22.7}{32}\times 960$
$=681L$ of oxygen at STP

Given,
100 L of air contains 30 L of oxygen at STP.
Volume of air that contains 681 L of oxygen at STP = $\frac{681\times 100}{30}=2270L$