Question

For the decomposition of $HI$ at $1000 K\left(2HI\to H_{2}+I_{2}\right),$
the following data were obtained

$\left[HI\right],M$	Rate of decomposition of $HI\left(mol L^{-1}s^{-1}\right)$
0.1	$2.75\times10^{-8}$
0.2	$11\times10^{-8}$
0.3	$24.75\times10^{-8}$

The order of reaction is:

• A. $1$
• B. $2$
• C. $0$
• D. $1.5$

Answer 1

Answer: (B)

$Rate-k\left[HI\right]^{n}$
$11\times10^{-8}=k\left[0.2\right]^{n} ....\left(i\right)$
$2.75\times10^{-8}-k\left[0.1\right]^{n} ....\left(ii\right)$
Dividing $eq\left(i\right)by eq.\left(ii\right) we get$
$4=2n, n=2$