For $2 SO X_{2} (g) + O X_{2} (g) 2 SO X_{3} (g)$ , $K_{c} = 200 L mo l^{- 1}$ at 500 K (use $R = 0.0821 L atm mo l^{- 1} K^{- 1}$ ). Which statements are correct at this temperature?

A $K_{p} = 4.87 at m^{- 1}$ for this reaction
BFor $SO X_{3} (g) SO X_{2} (g) + \frac{1}{2} O X_{2} (g)$ , $K_{c} = 0.0707 mo l^{1/2} L^{- 1/2}$
CFor $4 SO X_{2} (g) + 2 O X_{2} (g) 4 SO X_{3} (g)$ , $K_{c} = 400 L mo l^{- 1}$
D $K_{p}$ is numerically larger than $K_{c}$ for this reaction

Answer: A, B

Δ n_{g} = - 1

, so

K_{p} = K_{c} / (RT) = 200/41.05 = 4.87 at m^{- 1}

, which is smaller than

K_{c}

; (A) is true and (D) false. Reversing and halving gives

K_{c}^{'} = K_{c}^{- 1/2} = 0.0707

, so (B) is true. Doubling coefficients squares the constant, giving

40000

and not

400

, so (C) is false.