Question

During the kinetic study of the reaction, $2A+B \rightarrow C+D$ , following results were obtained

Run	$\left[\right.A\left]\right./molL^{- 1}$	$\left[\right.B\left]\right./molL^{- 1}$	Initial rate of formation of $D/molL^{- 1}min^{- 1}$
I	0.1	0.1	$6.0\times 10^{- 3}$
II	0.3	0.2	$7.2\times 10^{- 2}$
III	0.3	0.4	$2.88\times 10^{- 1}$
IV	0.4	0.1	$2.40\times 10^{- 2}$

Based on the above data which one of the following is correct?

• A. $rate=k\left[\right.A\left]\right.\left[\right.B\left]\right.^{2}$
• B. $rate=k\left[\right.A\left]\right.^{2}\left[\right.B\left]\right.$
• C. $rate=k\left[\right.A\left]\right.\left[\right.B\left]\right.$
• D. $rate=k\left[\right.A\left]\right.^{2}\left[\right.B\left]\right.^{2}$

Answer 1

Answer: (A)

$2A+B \rightarrow C+D$

Let $rate=K\left[\right.A\left]\right.^{m}\left[\right.B\left]\right.^{n}$

To get m- value divide (IV) by I and on solving $m=1$

Similarly, to get n devide (III) by (II) and on solving $n=2$

Hence $Rate=K\left[\right.A\left]\right.^{1}\left[\right.B\left]\right.^{2}$