Which of the following substances is most likely not an ionic compound?

Question

A hard, whitish substance that looks a bit like quartz.
A substance that conducts electricity upon dissociation .
A powdery substance that melts easily on your stovetop.
A solid that dissolves easily in water.

Answer 1

The third one; ionic compounds generally have high melting points, whereas covalent molecular compounds generally have low ones.

Answer 2

#3 Because that is the characteristic of a covalently bonded organic compound.

#1 could be an ionic salt. #2 is obviously ionic. #4 could be ionic.