For the reaction A_(g) $ \to $ B_(g) the value of the equilibrium constant at 300 K and 1 atm is equal to 100.0. The value of $\Delta $_rG for the reaction at 300 K and 1 atm in J mol^-1 is – xR, where x is _______. (Rounded off to the nearest integer)
[R = 8.31 J mol^–1K^-1 and ln 10 = 2.3)