Question

explain why melting point of NaCl is higher than that of AlCl3.

Answer 1

let us answer from point of chemical properties of ionic and covalent compounds.
we know that ionic compounds have more melting and boiling points than covalent compounds.
compare NaCl , AlCl3 .
NaCl is more ionic than AlCl3 because ionic character depends on size of cations as here anions are same more the size more the ionic character.
Na+ has more size than Al+++.
so the melting point of Nacl is much higher than that of Alcl3