The enthalpies of neutralization of HCIO₄ and CI₃C-COOH are 
- 13.5 kcal/g - equivalent and
- 13.5 kcal/g - equivalent respectively
when 40 g of solid NaOH is added to a mix of 1 g mol.
HClO₄ and 1 g mol CI₃C-COOH, sodium perchlorate and sodium trichloroacetate are formed in molar ratio of 3:1.
Then,

$∆\mathrm{H}$ for the reaction of NaOH with the mix. is 6.45 kcal.

$∆\mathrm{H}$ for the reaction of NaOH with the mix. is 13.8 kcal.

After reaction the total no. of moles of acid remained are 0.5 (HClO₄ and CI₃C-COOH)

After reaction the total weight of acid remained is 147.75 g. (HClO₄ + Cl₃Cl-COOH) and $∆\mathrm{H}$ for the reaction of NaOH with mix. is -13.8 kcal.