Understanding Second-Order Reactions: Exploring the Relationship Between Concentration and Half-Life

How does the initial concentration affect the half-life of a reaction?

As the initial concentration increases from 0.75 to 1.55 m in a reaction, t1/2 decreases from 60 to 29 s. What does this behavior indicate about the order of the reaction?

Answer:

The given behavior of the reaction where the half-life decreases with an increase in initial concentration indicates a second-order reaction.

Explanation: The question addresses the relationship between initial concentration and half-life in a reaction, specifically noting a decrease in t1/2 as the initial concentration increases from 0.75 to 1.55 m. This behavior is characteristic of a second-order reaction.

In second-order reactions, the half-life is inversely proportional to the initial concentration of the reactants. This means that as the initial concentration increases, the half-life decreases, and vice versa. Unlike first-order reactions, where half-life is independent of concentration, second-order reactions exhibit a clear dependence on reactant concentration.

Therefore, the observed decrease in half-life with increasing initial concentration in your scenario strongly suggests a second-order reaction.