Predict Which among the following substances is likely to have a relatively high melting point.(more than one answer may be selected)

Question

* P4
* CaCl2
* CCl4
* AlN
* CaC2
* None of the above

Answer 1

Most ionic compounds have high melting points; most covalent compounds have low melting points. That isn't a hard and fast rule (diamond, for example,doesn't follow this rule).
I see three compounds in your list with more than a little ionic character.

Answer 2

CaCl2, AIN, and CaC2