The correct sequence of increasing covalent character is represented by
- LiCl < NaCl < BeCl2
- BeCl2 < LiCl < NaCl
- NaCl < LiCl < BeCl2
- BeCl2 < NaCl < LiCl
Answer
(3) NaCl < LiCl < BeCl2
Solution
As per Fajans' rule, the smaller the cation and the higher its charge, the greater is its polarising power and hence the greater is the covalent character of the bond.
Be2+ is the smallest cation with +2 charge, so BeCl2 is the most covalent.
Li+ is smaller than Na+, so LiCl is more covalent than NaCl.
Increasing covalent character: NaCl < LiCl < BeCl2
Answer: (3)