Question
Among $$LiCl,BeC{l_2},BC{l_3}$$ and $$CC{l_4},$$ the covalent bond character follows the order
A.
$$LiCl < BeC{l_2} > BC{l_3} > \,CC{l_4}$$
B.
$$LiCl < BeC{l_2} < BC{l_3} > \,CC{l_4}$$
C.
$$LiCl < BeC{l_2} < BC{l_3} < \,CC{l_4}$$
D.
$$LiCl > BeC{l_2} > BC{l_3} > \,CC{l_4}$$
Answer :
$$LiCl < BeC{l_2} < BC{l_3} < \,CC{l_4}$$
Solution :
The electronegativity increases from left to right in any period, so the electronegativity follows the order
$$Li < Be < B < C$$
and hence, the covalent character of chlorides of these elements increase from $$Li$$ to $$C$$ because size of cation left to right decreases and according to Fajans’ rule covalent character increases.