Chemical Kinetics Question 2
Question 2 - 24 January - Shift 2
A student has studied the decomposition of a gas $AB_3$ at $25^{\circ} C$. He obtained the following data.
| $p(mm Hg)$ | 50 | 100 | 200 | 400 |
|---|---|---|---|---|
| Relative $ _{1 / 2}(s)$ | 4 | 2 | 1 | 0.5 |
The order of the reaction is
(1) 0.5
(2) 2
(3) 1
(4) 0 (zero)
Show Answer
Answer: (2)
Solution:
$t _{1 / 2} \propto(P_O)^{1-n}$
$\frac{(t _{1 / 2}^{t h})_1}{(t _{1 / 2})_2}=\frac{(P_0)_1^{1-n}}{(P _{0_2})_2^{1-n}}$
$\Rightarrow(\frac{4}{2})=(\frac{50}{100})^{1-n}$
$\Rightarrow 2=(\frac{1}{2})^{1-n}$
$\Rightarrow 2=(2)^{n-1}$
$\Rightarrow n-1=1$
$\Rightarrow n=2$
