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# How much heat would release when an aqueous solution containing 0.5 mol of $HNO_3$ is mixed with 0.3 mol of $OH^{-1}$? Given, enthalpy of neutralisation is -57.1 kJ.

(a) 28.5 kJ
(b) 17.1 kJ
(c) 1.7 kJ
(d) 2.85 kJ

0.5 mol $HNO_3 \equiv$ 0.5 mol $H^+$
$H^+ + OH^- \longrightarrow H_2O$ ; $\Delta H = -57.1$ kJ
Here, $OH^-$ = 0.3 mol
Thus, $OH^-$ is the limiting reactant.
When 1 mol of $OH^-$ ions are neutralised heat released = 57.1 kJ
0.3 mol of $OH^-$ ions are neutralised heat relaesed $= 57.1 \times 0.3$ = 17.13 kJ