Based on lattice energy and other considerations, which one of the following alkali metal chloride is expected to have the highest melting point ?

Options

A. `LiCl`
B. `NaCl`
C. `KCl`
D. `RbCl`

Answer

A

Explanation

The lattice energy of alkali metal halides decreases down the group due to increase in size of alkali metals. Thus,
`{:(underset(883^(@)C)(LiCl),underset(808^(@)C)(NaCl),underset(772^(@)C)(KCl),underset(717^(@)C)(RbCl),underset(645^(@)C)(CsCl)):}`