Question

$A+B$ $\to$ products. On doubling the concentration of $A$, rate gets doubled. Doubling the concentration of $A$ and $B$ also doubles the rate. The order of the reaction with respect to $A$ and $B$ is:

• A. $1,0$
• B. $0,1$
• C. $1,1$
• D. $1,2$

Answer 1

The correct option is A $1,0$

The expression for the rate of the reaction is $r=k\left[A{]}^n\right[B{]}^m-\left(1\right)$

When the concentration of $A$ is doubled and the concentration of $B$ remains the same, the rate expression becomes

$2r=k\left[2A{]}^n\right[B{]}^m-\left(2\right)$ ---- (given)

When the concentration of both $A$ and $B$ is doubled, the rate expression becomes $2r=k\left[2A{]}^n\right[2B{]}^n-\left(3\right)$

Divide equation (2) with equation (1) to obtain $n=1$
Divide equation (3) with equation (1) to obtain $n+m=1$
Hence, $m=0$

The overall order of the reaction is $=1+0=1$.