A decrease is the concentration of nitrogen monoxide (blank#1) between NO and H2 molecules. The rate of the forward reaction then (blank#2).

options #1 -

stabilizes the forward reaction

increases the energy

decreases the collisions

options #2 -

remains constant

increases

decreases

In the given situation, the reaction is-

NO + H2 ↔ Products

The rate of the reaction can be expressed (in terms of the decrease in the concentration of the reactants) as-

Rate = - dΔ[NO]/dt = - dΔ[H2]/dt

Now, if the concentration of NO is decreased there will be fewer molecules of the reactant NO which would decrease the its collision with H2. As a result the rate of the forward reaction would also decrease.

Ans) A decrease in the concentration of nitrogen monoxide decreases the collisions between NO and H2 molecules. the rate of the forward reaction then decreases.