Question

Heat of neutralization of any strong acid and strong base is always constant and $\Delta H=-57.3kJ$. This is because

• A. both the acid and base undergo complete ionization
• B. during neutralization salt and water are formed
• C. 1 mole of water is formed from $H^{+}$ and $O{H}^{-}$ ions
• D. the reaction is exothermic

Answer 1

Answer: (C)

The enthalpy of neutralization of any strong acid with a strong base is always the same, i.e., 57.1 kJ. This is because the strong acids, strong bases and the salts they form, are all completely ionized in dilute aqueous solution.
$N{a}^{+}=O{H}^{-}+H^{+}+C{l}^{-}\to N{a}^{+}+C{l}^{-}+H_{2}O$ or $H_{(aq)}^{+}+O{H}_{(aq)}^{-}\to H_2{O}_{(l)}$
i.e.; 1 mole of water is formed from $H^{+}$ and $O{H}^{-}$ ions.