Question

Which has the higher melting point, boiling point: toluene or magnesium hydroxide?

Answer 1

For a start, toluene (i.e. `"methylbenzene, "C_7H_8`) is a molecular species, with relatively weak intermolecular forces.

Explanation:

Magnesium oxide is a non-molecular species, held together by strong electrostatic bonds, which operates between oppositely charged ions throughout the entire lattice. The melting of the lattice requires that strong ionic bonds be disrupted, and hence high melting points.

On the other hand, toluene is a molecular species, for which boiling requires the disruption of intermolecular forces, which are much weaker than ionic ones.