Assuming that the exhaust gas (total pressure 1 atm) contains 0.2% CO, 12%CO2, and 3%O2 by volume, is the system at equilibrium with respect to the above reaction?

Assuming ideal gas conditions, the percentage in volume can be related to the percentage in pressure to calculate the partial pressure,

P (CO) = 0.002 bar

P (CO2) = 0.12 bar

P (O2) = 0.03 bar

Calculate the reaction quotient, Q

Q = [CO]^2[O2]/[CO2]^2

= (0.002) ^2 * (0.03) / (0.12) ^2

= 8.33 * 10^-6

If K > Q, a reaction will proceed forward, converting reactants into products. If K < Q, the reaction will proceed in the reverse direction, converting products into reactants. If Q = K then the system is already at equilibrium.

Since Q > K, hence the system is not in equilibrium. Instead, the system will shift to the left. As in, the reaction would occur in the reverse direction forming more CO2.

Upon addition of catalyst, the equilibrium of the reaction remains unchanged because catalyst affects the rate of the reaction and rate of reaction does not affect the equilibrium of the reaction.