Question

Which has the highest melting point?
A. LiCl
B.$BeC{l_2}$
C.$BC{l_3}$
D.$CC{l_4}$

Answer 1

Ionic compounds carry the same number of positive charge and negative charges which are arranged in the three-dimensional lattice structure. There is a strong force of attraction between the oppositely charged ions due to which they have a considerably high melting point.

Complete step by step answer:
Ionic compounds have a higher melting point and boiling point as compared to the covalent bond due to the strong force of attraction between the ions.
The compound LiCl is formed of lithium ion and a chlorine ion in which the lithium ion carries the positive charge and the chlorine ion carries the negative charge. Thus, LiCl is an ionic compound.
The compound $BeC{l_2}$ is formed from one beryllium atom and two chlorine atoms. The two chlorine atoms are joined to the beryllium atom by a covalent bond. Thus, $BeC{l_2}$ is a covalent compound.
The compound$BC{l_3}$is formed from one boron atom and three chlorine atoms. In this compound, the three chlorine atoms are attached to the boron atom by three covalent bonds. Thus, $BC{l_3}$ is a covalent compound.
The compound $CC{l_4}$ is formed from one carbon atom and four chlorine atoms. In this compound four chlorine atoms are attached to carbon by four covalent bonds. Thus, $CC{l_4}$ is a covalent compound.
Thus, LiCl will have the highest melting point.
Therefore, the correct option is A.

Note:
As we move along the period, the electronegative value increases, and the electronegativity difference among the element and the chlorine atom decrease with increases in the covalent character.