$\begin{array}{1 1}(a)\;\text{Fajans rule explains the covalent character of a chemical bond in ionic compounds}\\(b)\;\text{ Polarizing power of cation is inversely proportional to the size of the cation}\\(c)\;\text{ Polarisability of anion proportional to the size of the anion}\\(d)\;\text{ As the covalent character increases, the solubility of the ionic compound in water increases}\end{array}$