Consider the formation of a solution of aqueous potassium chloride. Write the thermochemical equations for
(a) the conversion of solid KCl into its gaseous ions and
(b) the subsequent formation of the solution by hydration of the ions. The lattice energy of KCl is -690 kJ mol_1, and the hydration energy of the ions is -686 kJ mol-1. Calculate the enthalpy of solution of KCl in kJ mol-1.