What is first order reaction?

In a first-order reaction, the rate is directly proportional to the concentration of a single reactant. The rate equation for a first-order reaction is expressed as Rate = k[A], where ‘k’ is the rate constant, and ‘[A]’ represents the concentration of the reactant. This means that as the concentration of the reactant decreases, the rate of the reaction also decreases proportionally. The half-life of a first-order reaction remains constant, and the reaction follows an exponential decay pattern. Many chemical reactions, such as radioactive decay and certain chemical decompositions, exhibit first-order kinetics.