Question

The absolute enthalpy of neutralisation of the reaction MgO(s) + 2HCl(aq) ------------>MgCl2 (aq) + H2O(l) will be:-


(1) Less than – 57.33 kJ mol–1 (2) –57.33 kJ mol–1
(3) Greater than –57.33 kJ mol–1 (4) 57.33 kJ mol–1

Answer 1

Hey dear,

● Answer -
A) less than -57.33 kJ/mol

● Explanation -
- The enthalpy of neutralization is enthalpy change that occurs when an acid and a base undergo a neutralization reaction to form salt and one mole water .
- When strong acid reacts with strong base enthalpy of neutralization is 57.33 kJ/mol.
- MgO is a weak base and requires some energy for ionization. Hence, less energy is released.
- Therefore, enthalpy of neutralization of MgO+HCl reaction is less than 57.33 kJ/mol.





Hope this helps you...

Answer 2

Answer:

3

Explanation:

The absolute value of enthalpy of neutralization of this reaction is greater than −57.33 kJmol

This is due to very high enthalpy of hydration of Mg 2+ ion. The change in enthalpy of this reaction is nearly -146 kJ.

Thus enthalpy of neutralization per mole of H + ion is nearly -73 kJ, which is greater than the enthalpy of neutralization strong acid against strong base i.e. -57.33 kJ.

Hope it helps..