Question

The enthalpy of neutralization of oxalic acid by a strong base is $-25.4k$ $cal{mol}^{-1}$. The enthalpy of neutralization of strong acid and strong base is $-13.7kcal$ ${eq}^{-1}$. The enthalpy of dissociation of oxalic acid is:
[Given: heat of neutralization will be $(2\times -13.7kcal)$]

• A. $1kcal$ ${mol}^{-1}$
• B. $2kcal$ ${mol}^{-1}$
• C. $18.55kcal$ ${mol}^{-1}$
• D. $11.7kcal$ ${mol}^{-1}$

Answer 1

The correct option is B $2kcal$ ${mol}^{-1}$

Enthalpy of neutralization $=13.7kcal/equivalent$

Oxalic acid is dibasic. Therefore, no. of equivalents = 2

$\therefore$ Enthalpy of neutralization of strong acid & strong base $=Enthalpyofneutralisation\times no.ofequivalent=-13.7\times 2=-27.4kcal/mol$

Enthalpy of dissociation of oxalic acid $=(27.4-25.4)=2kcal/mol$