To calculate the reaction quotient Q for the given reaction, we need to use the expression for Q, which is the ratio of the concentrations of products to the concentrations of reactants, each raised to the power of their stoichiometric coefficients in the balanced chemical equation.For the reaction: 2 NO g + O2 g 2 NO2 g , the expression for Q is:Q = [NO2]^2 / [NO]^2 * [O2] Now, we can plug in the given concentrations:Q = [0.17]^2 / [0.85]^2 * [0.12] Q = 0.0289 / 0.7225 * 0.12 Q = 0.0289 / 0.0867Q 0.333So, the reaction quotient Q for the equilibrium system at 298K with the given concentrations is approximately 0.333.