In a second-order reaction, if the concentration of reactant decreases, what happens to the rate?

In a second-order reaction, if the concentration of reactant decreases, what happens to the rate?

• A. It increases
• B. It decreases
• C. It stays the same
• D. It becomes zero

Answer: (B)

In a second-order reaction, the rate of the reaction is directly related to the concentration of reactants. The rate law for a second-order reaction can be expressed as rate = k[A]^2 for a single reactant A, where k is the rate constant. As the concentration of reactant A decreases, its squared concentration (A^2) also decreases. Because the rate is proportional to the concentration raised to the power of two, any reduction in A will lead to a corresponding reduction in the rate of the reaction. Thus, as A decreases, the overall rate of the reaction decreases as well. This relationship highlights the dependence of the reaction rate on the concentration of reactants, which is a fundamental concept in chemical kinetics. Therefore, in a second-order reaction, when the concentration of the reactant decreases, the rate of the reaction decreases.

In a second-order reaction, the rate of the reaction is directly related to the concentration of reactants. The rate law for a second-order reaction can be expressed as rate = k[A]^2 for a single reactant A, where k is the rate constant.

As the concentration of reactant A decreases, its squared concentration (A^2) also decreases. Because the rate is proportional to the concentration raised to the power of two, any reduction in A will lead to a corresponding reduction in the rate of the reaction. Thus, as A decreases, the overall rate of the reaction decreases as well.

This relationship highlights the dependence of the reaction rate on the concentration of reactants, which is a fundamental concept in chemical kinetics. Therefore, in a second-order reaction, when the concentration of the reactant decreases, the rate of the reaction decreases.