Question

The half-life of the reaction $X\rightarrow Y$, following first order kinetics, when the initial concentration of $X$ is $0.01 \,mol$ $L ^{1}$ and initial rate is $0.00352\,mol L^{-1}$ $min^{-1}$ will be

• A. $19.69 \,min$.
• B. $1.969 \, min$.
• C. $7.75 \, min$.
• D. $17.75 \, min$.

Answer 1

Answer: (B)

$\frac{dx}{dt}$ $=k\left[X\right]$ $\quad$ (For a first order reaction)
$0.00352=k\times0.01$
$\Rightarrow k=0.352$
$t_{1 /2}$ $=\frac{0.693}{k}$ $=\frac{0.693}{0.352}$
$=1.969 \,min$.