Question

The heat of neutralization of $NaOH$ with $HCl$ is $57.3kJ$ and with $HCN$ is $12.1kJ$ . The heat of ionization of $HCN$ is

• A. $+69.4KJ$
• B. $+45.2KJ$
• C. $-45.2KJ$
• D. $-69.4KJ$

Answer 1

Answer: (B)

The heat of neutralization of $NaOH$ with $HCl$ is $57.3kJ$ and with $HCN$ is $12.1kJ$ .
Heat of ionisation $+$ Heat of neutralisation of $NaOH$ with $HCN=$ Heat of neutralisation of $NaOH$ with $HCl$ .
Heat of ionisation $+12.1KJ=57.3kJ$
$\therefore$ Heat of ionisation $=57.3-12.1=45.2kJ$