Arrange the following in the decreasing order of their covalent character:
(A) LiCl
(B) NaCl
(C) KCl
(D) CsCl
Choose the most appropriate answer from the options given below

We need to arrange LiCl, NaCl, KCl, and CsCl in decreasing order of covalent character.

Key Concept: Fajans' Rules

According to Fajans' rules, covalent character of an ionic compound increases when:

• The cation is smaller (higher polarizing power)
• The cation has higher charge
• The anion is larger (more polarizable)

Analysis:

All four compounds have the same anion (Cl$$^-$$) and cations with the same charge (+1). The difference lies in the size of the cation:

$$\text{Li}^+ < \text{Na}^+ < \text{K}^+ < \text{Cs}^+$$

A smaller cation has greater polarizing power, leading to greater covalent character. Therefore, the decreasing order of covalent character is:

$$\text{LiCl} > \text{NaCl} > \text{KCl} > \text{CsCl}$$

$$\text{(A)} > \text{(B)} > \text{(C)} > \text{(D)}$$

Hence, the correct answer is Option C ((A) > (B) > (C) > (D)).