Question

For the decomposition of $HI$ at $1000K\left(2HI\to H_2+I_2\right)$ , the following data were obtained

Conc. Of HI(M)	Rate of decomposition of HI (mole/unit sec)
$0.1$	$2.75\times 10^{-8}$
$0.2$	$11\times 10^{-8}$
$0.3$	$24.75\times 10^{-8}$

The order of reaction is :

• A. 1
• B. 2
• C. 0
• D. 1.5

Answer 1

Answer: (B)

$Rate=k{\left[HI\right]}^n$
$11\times {\left(10\right)}^{-8}=k{\left(\left[0.2\right]\right)}^n...\left(i\right)$
$2.75\times {\left(10\right)}^{-8}=k{\left(\left[0.1\right]\right)}^n...\left(ii\right)$
Dividing eq. (i) by eq. (ii),
$4=2^n,n=2$