Question

The equilibrium constant K_p for the reaction, 2SO₂ (g) + O₂ (g) ⇋ 2SO₃(g)  is 900 atm^‒1 at 800 K. A mixture containing SO₃ and O₂ having initial partial pressure of 1 and 2 atm respectively is heated at constant volume to equilibrate. Calculate the partial pressure of each gas at 800 K. 

Answer 1

The system in the initial stage does not contain SO₂ .SO₃ will, thus, decompose to form SO₂ and O₂ until equilibrium is reached. The partial pressure of SO₃ will decrease. Let the decrease in partial pressure be 2x.

P_O2 = 0.0115 = 2.0115 atm 

P_SO3 = 1 - 2 x 0.0115 = 0.977 atm