Correct Answer - 779.3K
`DeltaG = DeltaH - T DeltaS`. When reaction is in equilibrium , `DeltaG =0.` `:. T = (DeltaH)/(DeltaS) = ( -113000J mol^(-1))/( - 145 JK^(-1)mol^(-1)) = 779.3K`.
For reaction to be spontaneous , `Delta G ` should be -ve which can be so if temperature is below ` 779.3K`