The magnitude of enthalpy change for neutralization of the reaction ,
`MgO(s)+2HCl(aq)rarrMgCl_(2)(aq)+H_(2)O(l)` (Given `H^(+)(aq)+OH^(-)(aq)rarrH_(2)O(l), -57 " kJ"//"mol"`) 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

Heat of neutralisation of strong acid and strong base is -57.33 KJ. MgO is weak base while HCl is strong acid. So the heat of neutralisation of MgO and HCl is lower than `-57.33 KJ ` because MgO requires some heat for ionisation , therefore the net released amount of heat is decreased.