Question

For the decomposition of $AB$ at $600$ $K$, the following data were obtained:

$\left[AB\right]mol{dm}^{-3}$	Initial rate of decomposition of $AB$ in $mol{dm}^{-3}{s}^{-1}$
$0.20$	$2.75\times {10}^{-8}$
$0.40$	$11\times {10}^{-8}$
$0.60$	$24.75\times {10}^{-8}$

The order of the decomposition of $AB$ is:

• A. $0$
• B. $1$
• C. $2$
• D. $1.5$

Answer 1

The correct option is C $2$

Let the rate of decomposition be given as:

$-\frac{dAB}{dt}=k[AB{]}^n$ where n=order of reaction

Substituting given data

$2.75\times {10}^{-8}=k[0.2{]}^n$-(1)

$11\times {10}^{-8}=k[0.4{]}^n$-(2)

From (1) and (2),

$[2{]}^n=\frac{11}{2.75}=4$

$n=2$

Order of decomposition$=2$