JIPMER2007ChemistryThermodynamics (C)
The absolute enthalpy of neutralisation of the reaction MgO (s)+2 HCl (a q) MgCl ₂(a q)+ H ₂ O (l) will be
Options
- Aless than -57.33 ~kJ ~mol ⁻¹
- B-57.33 ~kJ ~mol ⁻¹
- Cgreater than- 57.33 ~kJ ~mol ⁻¹
- D57.33 ~kJ ~mol ⁻¹
Correct answer
A. less than -57.33 ~kJ ~mol ⁻¹
Step-by-step solution
Heat of neutralisation of strong acid and strong base is -57.33 kJ . MgO is weak base while HCI is strong acid, so the heat of neutralisation of MgO and HCI is lower to -57.33 kJ because MgO requires some heat in ionisation, then net released amount of heat is decreased.