Question

Volume of oxygen gas at NTP necessary for complete combustion of 20 litre of propane, measured at $0^{o}C$ and 760 mm pressure is:

• A. 80 L
• B. 20 L
• C. 100 L
• D. 120 L

Answer 1

The correct option is C 100 L

Moles of propane$=\frac{PV}{RT}=\frac{1\times 20}{0.0821\times 273}=0.9moles$

Required reaction is --

$C_3{H}_8+5O_2\to 3C{O}_2+4H_{2}O$

Moles of $O_2$ required$=0.9\times 5=4.5moles$

Volume of $O_2$ required$=\frac{4.5\times 0.0821\times 273}{1}=100litres$