The heat of neutralisation of LiOH and HCl at 298k is 34.868kJ/mol. The heat of ionisation of LiOH will be?

It is observed that heat of neutralisation for strong acid against a strong base is always nearly the same,i.e.57.1 kJ no matter what acid or base is employed.However, when a weak base and a strong acid like LiOH and HCl are employed,the heat evolved is less than 57.1 kJ, which is 34.868 kJ/mol in this case. The reason for the lower value is that part of the heat energy evolved is utilised in complete ionisation of the weak base i.e. LiOH. 
Therefore, heat of ionisation of LiOH= 57.1kJ - Heat of neutralisation
                                                          = 57.1 - 34.868 kJ
                                                         = 22.232 kJ/mol

Hence, the heat of ionisation of LiOH is 22.232 kJ/mol.

  • 163
What are you looking for?