Question

Explain the process of melting and latent heat of fusion?

Answer 1

melting is a physical process. it is the conversion of a solid into liquid by changing the temperature .
while....
latent heat of fusion is the conversion of a liquid into gas without changing it's temperature .

Answer 2

Melting:
Most solids are packed in a tight crystal lattice with strong inter molecular forces of attraction. On passing heat, the internal binding energy of the crystal lattice gets overcome by the heat energy and the inter molecular forces of attraction weakens. This weakening of force causes instability in the crystal lattice and molecules separate out from each other and start moving in random directions. The instability in the crystal lattice initiates the melting of a substance. 

Latent heat of fusion:
After a substance is raised to the temperature of melting point, the heat added after this point doesn’t raise the temperature of melting point, the heat added after this point doesn’t raise the temperature of the substance, rather it is used completely to change the phase of the substance from solid to liquid. This heat supplied to the solid at its melting point is latent heat of fusion. It is defined as the heat energy required for completely changing 1 kg of a solid into liquid state at atmospheric pressure.