According to Fajan rules , the percentage of covalent character in an ionic compound increases . If the cation is highly charged or the cation is small and the anion is large or the cation has pseudo inert gas configuration . As a result of increased covalent character , the melting point decreases and solubility in less polar solvent increases .
Which of the following has the lowest melting point ?
A. LiCl
B. NaCl
C. KCl
D. RbCl .
