Final answer:
The final concentration of a reactant is always less than the initial concentration when using integrated rate laws in a chemical reaction.
Step-by-step explanation:
The question is concerned with the effect of integrated rate laws on the final concentration of a reactant or product as time progresses. When using integrated rate laws, which involve calculus to integrate the differential rate law, the final concentration of a reactant is always less than the initial concentration for a chemical reaction. This is because the laws are based on the premise that as time goes on, reactants are consumed to form products, thereby reducing the concentration of the reactants.
For zeroth, first, and second order reactions, the application of the appropriate integrated rate law will show a decrease in reactant concentration over time. Thus, the correct answer to the question is (c) Always. The final concentration should always be less than the initial concentration after using the integrated rate law.