For the gas-phase reaction

CHEMISTRY · Single correct · A Level · Chemistry · Gaseous equilibria (Kp) · Gaseous equilibria (Kp)

Problem

\text{H}_2(g) + \text{I}_2(g) \rightleftharpoons 2\,\text{HI}(g)

, the partial pressures at a particular instant are

P_{\mathrm{H_2}} = 0.80\,\text{atm}

P_{\mathrm{I_2}} = 0.60\,\text{atm}

, and

P_{\mathrm{HI}} = 1.20\,\text{atm}

. These values give

Q_{\text{fwd}} = 3.0

for the forward reaction as written. What is the reaction quotient

Q_{\text{rev}}

for the reverse reaction

2\,\text{HI}(g) \rightleftharpoons \text{H}_2(g) + \text{I}_2(g)

using the same set of partial pressures? (a)

0.400

(b)

0.111

(c)

0.333

(d)

3.0