Question
The correct sequence of increasing covalent character is represented by
A.
$$LiCl < NaCl < BeC{l_2}$$
B.
$$BeC{l_2} < NaCl < LiCl$$
C.
$$NaCl < LiCl < BeC{l_2}$$
D.
$$BeC{l_2} < LiCl < NaCl$$
Answer :
$$NaCl < LiCl < BeC{l_2}$$
Solution :
On the basis of Fajans' rule, lower the size of cation, higher will be its polarising power and higher will be covalent character.
$$\therefore {\text{Polarising}}\,{\text{power}} \propto \frac{1}{{{\text{size}}\,{\text{of}}\,{\text{cation}}}}$$
Covalent character $$ \propto $$ polarising power
So, the correct order is $$NaCl < LiCl < BeC{l_2}$$
( $$\because $$ The order of size of cation $${N{a^ + } > L{i^ + } > B{e^{2 + }}}$$ )