The absolute enthalpy of neutralization of the reaction,
`MgO(s)+2HCl(aq.)+H_(2)O(l)` will be

Options

A. Less than - 57.33 kJ `mol^(-1)`
B. `-57.33 kJ mol^(-1)`
C. Greater than `-57.33 kJ mol^(-1)`
D. `57.33 kJ mol^(-1)`

Answer

A

Explanation

The enthalpy of neutralization of one equivalent of a strong base and that of an acid is equal to 57.33 kJ/mol. But for a weak base like MgO some amount of energy will be required for the dissociation of base and the heat evolved will be less.