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Q.
What volume of dioxygen is required for complete combustion of $2$ volumes of acetylene gas at $NTP$?
Some Basic Concepts of Chemistry
Solution:
$\underset{2 \text { vol. }}{ C _2 H _2}+\underset{\frac{5}{2} \text { vol. }}{\frac{5}{2} O _2} \to \underset{2 \text{vol}}{2 CO _2}+ H _2 O$
$1$ vol. of $C_2H_2$ requires =$\frac{5}{2}$ vol. of $O_2$
$2$ vol. of $C_2H_2$ requires =$\frac{5}{2}\times 2 = 5$ vol. of $O_2$