Question

A gas phase reaction is,
$A\left(g\right)+2B\left(g\right)\to C\left(g\right)$
the reaction was carried out with stoichiometric proportions's of $A$ and $B$ and the following data is obtained

Half-life (min)	10	160
Initial pressure of $A$(atm)	40 atm	10 atm

What is overall order of reaction?

Answer 1

$t_{1/2}\alpha \frac{1}{(p{)}^{n-1}}$ where p=pressure, $n=$ order of reaction

$\frac{(t_{1/2}{)}_1}{(t_{1/2}{)}_2}=(\frac{P_2}{P_1}{)}^{n-1}$

$\frac{10}{160}=(\frac{10}{40}{)}^{n-1}$

$\frac{1}{16}=(\frac{1}{4}{)}^{n-1}$=> n-1=2 or n=3

Overall order $=3$