Question

Calculate the volume of oxygen at S.T.P. to burn $20 mL$ of acetylene at S.T.P.

Answer 1

SOLUTION : Acetylene on burning is converted to $CO _{2}$ and $H _{2} O$.

$\begin{array}{l}2 C _{2} H _{2}+5 O _{2}=4 CO _{2}+2 H _{2} O \\2 \text { vol. } \quad 5 \text { vol. }\end{array}$

$\because \quad 2$ vol. acetylene require 5 vol. $O_{2}$ for combustion at S.T.P.

$\therefore 20 mL$ acetylene will require $\frac{5 \times 20}{2} mL =50 mL$ oxygen.