The half-life of a second-order reaction does depend on [a]0, unlike that of a first-order reaction. the quantity [a]0 remains the samethe half-life of a second-order reaction does depend on [a]_0, unlike that of a first-order reaction. the quantity [a]_0 blank over the course of the reaction. as a result, since \large{t_{1/2} = \frac {1}{k[a]_0}} in a second-order reaction, the half-life of a second-order reaction blank as the reaction proceeds. over the course of the reaction. as a result, since t1/2=1k[a]0 in a second-order reaction, the half-life of a second-order reaction decreases in concentrationthe half-life of a second-order reaction does depend on [a]_0, unlike that of a first-order reaction. the quantity [a]_0 blank over the course of the reaction. as a result, since \large{t_{1/2} = \frac {1}{k[a]_0}} in a second-order reaction, the half-life of a second-order reaction blank as the reaction proceeds. as the reaction proceeds.