Question

In which of the following reactions, the heat liberated is known as "heat of combustion"?

• A. $H^{+}(aq)+OH^{-}(aq)\to H_{2}O(l)+\text{ heat}$
• B. $C\text{(graphite)}+\frac{1}{2}O_{2}(g)\to CO(g)+\text{heat}$
• C. $CH_{4}(g)+2O_{2}(g)\to CO_{2}(g)+2H_{2}O(l)+\,\text{heat}$
• D. $H_{2}SO_{4}(aq)+H_{2}O(l)\to H_{2}SO_{4}(aq)+ \text{heat}$

Answer 1

Answer: (C)

The amount of heat evolved or absorbed when $1$ mole of the substance is completely oxidised is called heat of combustion. For example,
$CH_{4}(g)+2O_{2}(g)\to CO_{2}(g)+2H_{2}O(l)+\text{heat}$