Account for the change when no2cl is added using the reaction quotient qc.

Missing question: Will the concentration of NO₂ increase, decrease, or remain the same when the equilibrium NO₂Cl (g) + NO (g) → NOCl (g) + NO₂ (g) is disturbed by the following events?

According Le Chatelier's principle when concentration of reactants increase (in this case NO₂Cl), concentration of products also increase (in this case NO₂).