The thermodynamic property that measures the extent of molecular disorder is called entropy. The direction of a spontaneous process for which the energy is constant is always the one that increases the molecular disorder. Entropy change of phase transformation can be calculated using Trouton's formula `(DeltaS= (DeltaH)/(T))`. In the reversible adiabatic process, however, `DeltaS` will be zero. The rise in temperature in isobaric and isochoric conditions is found to increase the randomness or entropy of the system. `DeltaS= 2.303 C log (T_(1)//T_(2)), (C = C_(P) or C_(V))`
The melting point of a solid is 300K and its latent heat of fusion is 600 cal `mol^(-1)`. The entropy change for the fusion of 1 mole of the soli (in cal `K^(-1)`) at the same temperature would be:

Options

A. 200
B. 2
C. 0.2
D. 20

Answer

B

Explanation

`Delta S` for phase Transition
`= (Delta H "phase transition")/("Temperature") = (600)/(300) = 2`