Question

KClKCl has a lattice energy of −701 kJ/mol.−701 kJ/mol. Consider a generic salt, ABAB , where A2+A2+ has the same radius as K+,K+, and B2−B2− has the same radius as Xl−.Xl−. Estimate the lattice energy of the salt ABAB .

Answer 1

Explanation:

It is given that lattice energy is -701 kJ/mol.

Whereas it is known that realtion between lattice energy and radius is as follows.

               Lattice energy $\propto \frac{Z_{+}Z_{-}}{r}$

where,          $Z_{+}$ = +2,    and $Z_{-}$ = -2

Therefore, lattice energy of AB = $4 \times \text{lattice energy of KCl}$

                                                    = $4 \times -701 kJ/mol$

                                                    = -2804 kJ/mol

Thus, we can conclude that lattice energy of the salt ABAB is -2804 kJ/mol.