The equilibrium constants of the following isomerisation reaction at 400 K and 298 K are 2.07 and 3.42 respectively. cis-butene k _ -1 k ₁ trans-butene Which of the following is/are correct? I. The reaction is exothermic II. The reaction is endothermic III. At 400 ~K 50 % of cis-butene and 50 % of trans-butene are present at equilibrium IV. Both at 298 K and 400 ~K , k ₁= k _ -1