What is the consequence on melting point for a pure substance with stronger intermolecular forces? Explain.
The higher the melting point is, the stronger the intermolecular forces are.
When a substance is in a solid state, its particles are very close together due to their intermolecular (attractive) forces.
During melting, the particles gain enough energy to overcome those attractions and enter a liquid state, in which they can flow past one another.
Temperature is proportional to the average kinetic energy of the particles. If the melting point is high, that means a large amount of energy is needed to overcome the strength of intermolecular forces.
Likewise, if the melting point is low, it doesn't take that much energy to break free of those attractions.