Answer:
B.) and D.)
Explanation:
A.) is incorrect because the reaction technically never stops if the system remains in tact. Rather, there is just an equal amount of forward and reverse reactions occurring. This means that the overall concentrations of the reactants and products stays the same.
B.) is correct because when the concentrations of the reactants and products remain unchanged, then equilibrium is reached.
C.) in incorrect because, at this point, the concentrations of the reactants are still decreasing and the products are still increasing. If point 2 is specifically referencing the intersection of the lines, this cross symbolizes equal concentrations of the reactants and product. Keep in mind that equal concentrations does not equal equilibrium.
D.) is correct because a reaction moving forward means that mostly product is being created. In other words, the concentration of the product should be increasing. Meanwhile, the concentration of the reactants decrease because they are being used to create the product. As seen in the graph, the product (H₂O₂) is rapidly increasing in concentration. Meanwhile, the concentrations of the reactants (O₂ and H₂O) are decreasing as they would in a forward reaction.
