Chemistry - Chemical Kinetics Question with Solution | TestHub

Slowest step is rate determining step, hence the rate will be given by slowest step.
Thus$\mathrm{r}=\mathrm{K}\left[\mathrm{A}\right]\left[{\mathrm{B}}_2\right]$. Where$\left[\mathrm{A}\right]$is intermediate, which is derived from
${\mathrm{K}}_{\mathrm{c}}=\frac{\left[\mathrm{A}\right]\left[\mathrm{A}\right]}{\left[{\mathrm{A}}_2\right]}\mathrm{}\mathrm{}$or$\left[\mathrm{A}\right]=\left[{\mathrm{K}}_{\mathrm{c}}{]}^{1/2}\right[{\mathrm{A}}_2{]}^{1/2}$
$\mathrm{r}=\mathrm{K}\times \left[{\mathrm{K}}_{\mathrm{c}}{]}^{1/2}\right[{\mathrm{A}}_2{]}^{1/2}\left[{\mathrm{B}}_2\right]=\mathrm{K}\left[{\mathrm{A}}_2{]}^{1/2}\right[\mathrm{B}]$.
Thus, order is$0.5+1=1.5$