The correct order of melting point of alkali metal chlorides is:
The correct option is A NaCl>KCl>CsCl
Melting point depends on lattice energy. Greater the lattice energy, greater is the melting point.
Lattice energy depends on the size of the ions involved. Smaller the internuclear distance, larger the lattice energy.
Hence, the correct order is: NaCl>KCl>CsCl