The free energy change of a reaction is given by `DeltaG = DeltaH -TDeltaS`
For a reaction to be spontaneous , `DeltaG` shouldbe `-ve`.
If both `DeltaH`and `DeltaS` are positive, `DeltaG` can be `-ve` if `T Delta S gt DeltaH`in magnitudee. Thus, entropy factor should dominate over enthalpy factor. Such reactions are therefore, called entropy driven.This can happen in either of the following two ways `:`
(i) `DeltaS` shoul beso learge that even if T is low , `T DeltaS` should be greater than`DeltaH`
(ii) If` DeltaS`is small, T should be so large that`T DeltaS gt DeltaH`