Question

Equal volumes of methanoic acid and sodium hydroxide are mixed, if $x$ is the heat of formation of water, then heat evolved on neutralisation is

• A. twice of x
• B. equal to x
• C. more than x
• D. less than x

Answer 1

Answer: (D)

Methanoic acid is a weak acid and therefore, energy will be required for its dissociation. Thus, the energy released on neutralisation of methanoic acid and sodium hydroxide giving salt and water will be less than the heat evolved during the formation of water.