At 700 K, the equilibrium constant K_p, for the reaction 2 SO₃ (g) ⇌ 2 SO₂ (g) + O₂ Is 1.8 X 10^-3 kPa. What is the numerical value in moles per liter of K_c for the reaction at the same temperature?

Relation between K_{p and Kc is given as:
Kp = Kc (RT) ^∆n
Kc = Kp / (RT) ^∆n
T = 700 K
R = 8.314 J mol ^-1 K^-1
∆n = (2 + 1) – 2 = 1
Kp = 1.8 X 10^-3 kPa = 1.8 Pa
Therefore,
Kc = 1.8 Pa / (8.314 J mol ^-1 K^-1) (700)¹
= 3.09 X 10^-7 mol m-3}

Hence, the numerical value in moles per liter of K_c is equal to 3.09 X 10^-7 mol m_-3