Acetic acid (ethanoic acid) and hydrochloric acid react with `KOH` solution. The enthalpy of netralisation of ethanoic acid is `-55.8 kJ mol^(-1)` while that of hydrochloric acid is `-57.3 kJ mol^(-1)`. Can you think of how are these different?

Explanation

Enthalpy of neutralization for HCl `=-57.3 kJ mol^(-1)`.
Enthalpy of neutralization for `CH_(3)COOH = -55.8 kJ mol^(-1)`
In case of neutralization of `CH_(3)COOH`, the part of heat released `[-55.8 - (-57.3) = + 1.5 kJ]` is used up in dissociation of acetic acid and thus heat gives out is lesser than 57.3 kJ.