Question

The half-life of $2$ sample are $0.1$ and $0.4$ seconds. Their respective concentration are $200$ and $50$ respectively. What is the order of the reaction?

• A. 0
• B. 2
• C. 1
• D. 4

Answer 1

Answer: (B)

2

$t_{1/2}\propto a^{1-n}\Rightarrow \frac{0.1}{0.4}$ = $\frac{(200{)}^{1-n}}{(50{)}^{1-n}}\Rightarrow \frac{1}{4}$ = ${\left[\frac{4}{1}\right]}^{1-n}={\left[\frac{1}{4}\right]}^{n-1}\Rightarrow \frac{1}{4^1}=\frac{1}{4^{n-1}}$ $\therefore$ $n-1$=$1$; $n=2$
Option B is correct.