Chemical Kinetics - Result Question 38
####38. The rate of a first order reaction is $1.5 \times 10^{-2}$ $mol L^{-1} min^{-1}$ at $0.5 M$ concentration of the reactant. The half life of the reaction is [2004]
(a) $0.383 min$
(b) $23.1 min$
(c) $8.73 min$
(d) $7.53 min$
Show Answer
Solution:
- (b) For a first order reaction, $A \to$ products
$r=k[A]$ or $k=\frac{r}{[A]}$
$\Rightarrow k=\frac{1.5 \times 10^{-2}}{0.5}=3 \times 10^{-2}$
Further, $t _{1 / 2}=\frac{0.693}{k}=\frac{0.693}{3 \times 10^{-2}}=23.1 min$.
