Experimental kinetic tracking data for a reaction conducted at a rigidly constant temperature reveal — Chemical Kinetics Chemistry Question
Question
Experimental kinetic tracking data for a reaction $A \rightarrow B$ conducted at a rigidly constant temperature reveals that as the absolute initial concentration $[A]_0$ is doubled, the reaction's half-life $t_{1/2}$ is also exactly doubled. Which of the following resulting conclusions is/are mathematically sound?
💡 Solution & Explanation
Given $t_{1/2} \propto [A]_0$, this proportionality matches $t_{1/2} \propto [A]_0^{1-n}$ only when $n = 0$. Thus, it is a zero-order reaction (A is correct). For zero order, Rate $= k[A]^0 = k$, meaning the rate is independent of concentration (B is correct). The unit of $k$ equals the unit of rate, $\text{mol L}^{-1} \text{ s}^{-1}$ (C is correct). D is false; the straight line is $[A]_t = [A]_0 - kt$, which intersects the y-axis at $[A]_0$, not the origin.