If for a certain reaction ∆rH is 30 kJ mol-1 at 450 K, the value of ∆rS (in JK-1 mol-1) for which the same reaction will be spontaneous at the same temperature is

For spontaneous reaction, ∆rG  must be less than zero. So, ΔrG=ΔrH−TΔrS<0 or, ΔrS>ΔrHT>30,000450=66.67J∴For reaction to be spontaneous, the value of ∆rS  must be greater than 66.67 J