Question

The rate of reaction; $A+2B\to \text{Products}$ is given by,

$-\frac{d\left[A\right]}{dt}=k\left[A\right]{\left[B\right]}^2.$ If B is present in large excess, the order of reaction is:

• A. 3
• B. 2
• C. 1
• D. zero

Answer 1

The correct option is C 1

The given relation is:

$A+2B\to \text{Product}$

Rate $\Rightarrow \frac{-d\left[A\right]}{dt}=k\left[A\right]{\left[B\right]}^2$ (given)

If $\left[B\right]$ is present in large excess, then change in concentration of $\left[B\right]$ does no alter the rate means rate becomes independent on $\left[B\right]$

Hence order is counted only for ${\left[A\right]}^1$

Overall order $=1$