Question

Which has the highest melting point?

• A. $LiCl$
• B. ${BeCl}_2$
• C. ${BCl}_3$
• D. ${CCl}_4$

Answer 1

The correct option is A $LiCl$

As for $LiCl$, it is an ionic compound with the high degree of covalent character due to the polarising power of the $L{i}^{+}$ (high charge-to-size ratio due to small ionic radius of $L{i}^{+}$). The covalent character would reduce the melting point of $LiCl$ as the lattice is affected. So even though $L{i}^{+}$ has a higher charge-to-size ratio than $N{a}^{+}$, its melting point is lower due to a high covalent character.

But here LiCl has the highest melting point.