For the reaction SO2 (g) + ${1 \over 2} O_2(g) \leftrightharpoons$ SO3(g). if KP = KC(RT)x where the symbols have usual meaning then the value of x is: (assuming ideality)

Question

For the reaction SO₂ (g) + ${1 \over 2} O_2(g) \leftrightharpoons$ SO₃(g).
if K_P = K_C(RT)^x where the symbols have usual meaning then the value of x is: (assuming ideality)