The melting of ice is an endothermic reaction which means it requires energy or the enthalpy of reaction is positive
For a reaction to be spontaneous the change in free energy should be negative.
ΔG = ΔH - TΔS
Where
ΔG = change in free energy
ΔH = change in enthalpy
ΔS = change in entropy
Now in any case enthalpy will be positive (endothermic)
Here as ice is melting the process if going from less random phase to more random or disorder phase so there is an increase in entropy or ΔS = positive
In order to make ΔG negative, the ΔH < TΔS , this is possible only at higher temperature
Hence, At high temperature the process of melting of ice is spontaneous process.
At low temperature
ΔH > TΔS, and ΔG will become positive making the reverse process (freezing) spontaneous and melting of ice non spontaneous.
