Question

The following reaction is first--order in A and first-order in $B$: $A+B\to poduct$
$Rate=k\left[A\right][B$
Relative rate of this reaction in vessel I and II of equal volume is:

• A. 1:1
• B. 1:2
• C. 2:1
• D. 1:4

Answer 1

The correct option is B 1:2

The concentration of B in both vessels is same. The concentration of A in vessel II is twice the concentration in vessel I.
For vessel I, $r=k\left[A\right]\left[B\right]$......(1)
For vessel II, $r^{\prime }=k\times 2\left[A\right]\left[B\right]$......(2)
Divide equation (2) with (1).
$\frac{r^{\prime }}{r}=\frac{k\times 2\left[A\right]\left[B\right]}{k\left[A\right]\left[B\right]}=2$
Hence, the relative rate of this reaction in vessel I and II of equal volume is 1:2.