Chemical Kinetics - Result Question 29
####29. During the kinetic study of the reaction, $2 A+B \to C+D$, following results were obtained:
\begin{tabular}{|c|c|c|c|} \hline Run & {$[A] / mol L^{-1}$} & {$[B] / mol L^{-1}$} & \begin{tabular}{l} Initial rate of \\ formation of \\ $D / mol L^{-1} min^{-1}$ \end{tabular} \\ \hline I & 0.1 & 0.1 & $6.0 \times 10^{-3}$ \\ \hline II & 0.3 & 0.2 & $7.2 \times 10^{-2}$ \\ \hline III & 0.3 & 0.4 & $2.88 \times 10^{-1}$ \\ \hline IV & 0.4 & 0.1 & $2.40 \times 10^{-2}$ \\ \hline \end{tabular}
Based on the above data which one of the following is correct?
[2010]
(a) $rate=k[A]^{2}[B]$
(b) rate $=k[A][B]$
(c) $rate=k[A]^{2}[B]^{2}$
(d) $rate=k[A][B]^{2}$
Show Answer
Solution:
- (d) In case of (II) and (III), keeping concentration of $[A]$ constant, when the concentration of $[B]$ is doubled, the rate quadruples. Hence, it is second order with respect to B. In case of I & IV, keeping the concentration of [B] constant, when the concentration of $[A]$ is increased four times, rate also increases four times. Hence, the order with respect to $A$ is one. hence
$ \text{ Rate }=k[A][B]^{2} $
