Please see attached file.

PROBLEM – 2
Part – a)
Consider a pure substance, say metal. At the melting point of the substance, when the quantities P and T are constant, metal sample will be partly molten, if heat is supplied. Equilibrium exists between the liquid and solid phase.
The kinetic energy, the potential energy and the entropy are higher for the liquid as compared to those of the solid.
The potentials, namely, Internal Energy (U), Enthalpy (H), Gibbs Free Energy (G), Helmholtz Free Energy...