Question

The decomposition of a compound is found to follow a first-order rate law. If it takes 15 min for 20% of the original material to react, the specific rate constant is ________. ($inmi{n}^{-1}$ )

[If the answer is X, write the value of 1000X in nearest integer value possible]

Answer 1

We know for the first order,

$k=\frac{2.303}{t}log\frac{a}{a-x}$

Given that,

$t=15;x=0.2a$ where $a=$ initial concentration.

$k=\frac{2.3}{15min}log\left(\frac{a}{a-0.20a}\right)$ $=0.01488$ $mi{n}^{-1}$
$0.01488\times 1000\approx 15$
Ans-$15$