Question

The correct sequence of increasing covalent character is represented by :

• A. BeCl${}_2$ < NaCl < LiCl
• B. NaCl < LiCl < BeCl${}_2$
• C. BeCl${}_2$ < LiCl < NaCl
• D. LiCl < NaCl < BeCl${}_2$

Answer 1

The correct option is B NaCl < LiCl < BeCl${}_2$

Let us consider $M=Na/Li/Be$ and $X=Cl$

The covalent character in $M-X$ bond will depend on the eletronegativity difference $\left(△EN\right)$.

If $\left(△EN\right)$ is small, then the bond will have more covalent character.

If $\left(△EN\right)$ is large, then the bond will have less covalent character.

$\to$ In a periodic table, electronegativity increases from top to bottom and from left to right.

As $X$ is same in all the atoms.

We can give its order only using eletronegativities of $M$, i.e. $Na,Li,Be$

Order of electronegativities is $Na<Li<Be.$

Hence, the increasing order of covalent character is $NaCl<LiCl<Be{Cl}_2$

Therefore, option B is correct.