If `Na^(+)` ion is larger than `Mg^(2+)` ion and `S^(2-)` ion is larger than `Cl^(-)` ion, which of the following will be least soluble in water?

Options

A. Sodium chloride
B. Sodium sulphide
C. Magnesium chloride
D. Magnesium sulphide

Answer

D

Explanation

Higher the lattice energy lower the solubility. Out of the four combinations possible, the lattice energy of MgS is higher than those of `Na_2S, MgCl_2 and NaCl` and hence MgS is the least soluble.