Given that the data for neutralization of a weak acid (HA) and strong acid with a strong base is:

$$\begin{gathered} \mathrm{HA}+\mathrm{OH}\to \mathrm{A}+{\mathrm{H}}_2\mathrm{O};\Delta \mathrm{H}=-41.80 \mathrm{k}\mathrm{J} \\ {\mathrm{H}}^{+}+\mathrm{OH}\to {\mathrm{H}}_2\mathrm{O}; \Delta \mathrm{H}=-55.90 \mathrm{k}\mathrm{J} \end{gathered}$$

The enthalpy of dissociation of weak acid would be

It is given that, the heat of neutralization for a strong acid with a strong base is $-55.90\mathrm{ }\mathrm{k}\mathrm{J}$.

For a weak acid HA, some of this heat is consumed by completely dissociating of the acid.

$$\begin{gathered} {\mathrm{\Delta H}}_{\text{(Dissociation) }}={\mathrm{\Delta H}}_{\left(\mathrm{HA}\right)}-{\mathrm{\Delta H}}_{\text{(strongacid+strongbase) }} \\ {\mathrm{\Delta H}}_{\text{(Dissociation) }}=-41.80-(-55.90) \\ {\mathrm{\Delta H}}_{\text{(Dissociation) }}=14.10 \mathrm{kJ} \end{gathered}$$