Chemical Kinetics - Result Question 29
29. Consider a reaction, $a G+b H \rightarrow$ products. When concentration of both the reactants $G$ and $H$ is doubled, the rate increases by eight times. However, when concentration of $G$ is doubled keeping the concentration of $H$ fixed, the rate is doubled. The overall order of the reaction is
(2007, 3M)
(a) $ 0$
(b) $ 1$
(c) $ 2$
(d) $ 3$
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Answer:
Correct Answer: 29. (d)
Solution:
- Rate $\propto[G]^{m}[H]^{n}$
$\because$ Rate is double on doubling the concentration of $G$ and maintaining $H$ constant, $m=1$, i.e. $R \propto[G]$.
Also, when both concentration of $G$ and $H$ are doubled, rate increases by a factor of $8$ . Here rate is increasing by a factor of $ 2$ due to $G$ (first order in $G$ ), therefore, factor due to $H$ is $4$ .
$ \begin{array}{lll} \Rightarrow & R \propto[H]^{2} \\ \Rightarrow & \text { Overall order } & =m+n=1+2=3 \end{array} $
BETA
