Question

The amount of heat evolved when $0.50$ mole of HCl is mixed with $0.30mole$ of NaOH solution is

• A. $57.1kJ$
• B. $28.55kJ$
• C. $11.42kJ$
• D. $17.13kJ$

Answer 1

Answer: (D)

$17.13kJ$

Answer 2

: $0.50$mol of HCl $\equiv 0.50$ mol of $H^{+}$

$0.30$ mol of NaOH $\equiv 0.30$ mol of $OH^{-}$

$H^{+} + OH^{-} \rightarrow H_{2}O$ (Neutralisation)

$0.30$ mol of HCl $\equiv 0.30$ mol of $H^{+}$

or $0.30$ mol of $H^{+} \equiv 0.30$ mol of $OH^{-}$

Heat evolved with 1 mol $H^{+} = 57.1kJ$

Heat evolved with $0.30$ mol

$H^{+} = 87.1 \times 0.30 = 17.13kJ$