Question

In which of the following reactions, the heat of neutralization will be the highest?

• A. $HCl\,\,\text{and}\,\,NaOH$
• B. $N{{H}_{4}}OH\,\,\text{and}\,\,HCl$
• C. $NaOH\,\text{and}\,C{{H}_{3}}COOH$
• D. $C{{H}_{3}}COOH\,\text{and}\,N{{H}_{4}}OH$

Answer 1

Answer: (A)

$HCl\,\,\text{and}\,\,NaOH$

Answer 2

Heat of neutralisation is maximum (i.e., approximately 13.7 kcal/mole) for the neutralisation of a strong acid and a strong base. If one of them is weak, then heat of neutralisation also decreases (due to being consumed in ionization of weak electrolyte). Hence, here the heat of neutralisation of $HCl$ and $NaOH$ will be the highest.