Question

The heat released in the neutralisation of HCI and NaOH is 13.7 kcal/mol, the heat
released on neutralisation of NaOH with ${CH}_{3}COOH$ is 3.7 kcal/mol.
The ${\Delta H}^{}$ of ionisation of ${CH}_{3}COOH$ is:

• A. 10.2 kcal
• B. 10 kcal
• C. 3.7 kcal
• D. 9.5 kcal

Answer 1

The correct option is A 10.2 kcal

1) In the neutralization process ions come to each other and form salt and water.

2) HCL is strong acid means $H^{+}+C{L}^{-}$ and $NaOH$ is strong base means $N{a}^{+}+O{H}^{-}$ So there is not any energy loss to break HCL or NaOH. total energy will come as neutralisation.

3) In Case of $NaOH+C{H}_{3}COOH$ $NaOH$ is strong base means $N{a}^{+}+O{H}^{-}$ But $C{H}_{3}COOH$ is a weak acid so have to give some energy to form $CHCO{O}^{-}+H^{+}$ So total released energy= total energy in case of (strong acid + strong base) - energy require to form ions. $3.7=13.7$ - energy require to form ions energy require to form ions$=10.00kcal$. only $C{H}_{3}COOH$ is weak nature So this enegy is ionisation energy of $C{H}_{3}COOH.$