Answer:
B. At the end of the reaction, both product and reactants are of a constant concentration.
Step-by-step explanation:
- Option A and C are similar as they both refer to constant concentration of product and reactant respectively in first half. As in the graph, the concentration of reactant and product changes (concentration of reactant decreases and concentration of product increase) with time in the first half
of the reaction. This made both A and C option wrong. - Option D is also wrong as at the end of reaction
the line of concentration of product and reactant do not coincide which means they are not equal. - Option B is correct as we take the end of reaction at the point where the concentration of reactant and product won't change much or become constant
first half time is the when concentration of reactant reduces to 50% of initial concentration which you can nearly assume on or before the point of intersection of both the concentration graphs.
end of reaction is the time when the reaction completes which is theoretically infinite but generally we take end of the reaction as the time when the slope of concentration curve becomes nearly zero or the time when change in concentration of reactant and product is negligible.