At a certain fixed temperature, the time required for exactly completion of a specific first-order r — Chemical Kinetics Chemistry Question

💡 Solution & Explanation

For a first order reaction, the time required for 50% completion is one half-life ($t_{1/2}$). The time required for 75% completion represents the time for the concentration to drop to 25% (or $1/4$) of its initial value. This exactly corresponds to $2$ half-lives ($1 \rightarrow 1/2 \rightarrow 1/4$). Therefore, $t_{75\%} = 2 \times t_{50\%}$. The value of $X$ is exactly 2.