Question

The heat of neutralization of NaOH with HCl is 57.3 KJ and with HCN is 12.1 KJ. The
heat of ionization of HCN is
A. +69.4 KJ B. +45.2 KJ C. - 45.2 KJ D. -69.4 KJ

Answer 1

$\pink{Given}$

• Heat of neutralization of NaOH with HCl = 57.3 KJ

• Heat of neutralization of NaOH with HCN = 12.1 KJ

$\pink{To \: Find}$

Heat of ionization of HCN

$\pink{Concept}$

Heat of neutralization of a weak acid/base like HCN = Heat of neutralization of a strong acid and a strong base - ionization energy of the weak acid or the base.

$\pink{Calculations}$

Given,

Heat of neutralization of NaOH with HCl = 57.3 KJ

Heat of neutralization of NaOH with HCN = 12.1 KJ

Putting in the formula :-

Heat of neutralization of a weak acid/base like HCN = Heat of neutralization of a strong acid and a strong base - ionization energy of the weak acid or the base.

=> Heat of ionization = 57.3 - 12.1

=> Heat of ionization = 45.2 KJ

$\boxed{ \: \red{ heat \: of \: ionization \: = 45.2\: KJ} \: }$