According to Gibb's free energy, ΔG=ΔH−TΔS Reaction is non spontancous i.e. ΔG>0 at 298K. As the temperature increases from 298K to 350K. The reaction becomes spontaneous i.e. ΔG<0. ΔG=ΔH−TΔS ΔG<0 When ΔH and ΔS are +ve then, ΔG will be positive till ΔH>TΔS. When the temperature is increased further ΔH becomes less than TΔS i.e. ΔH<TΔS and ΔG becomes −ve. Thus, reaction becomes spontancous.