For a reaction $r=k[A][B]^2$, if concentration of $A$ is doubled the rate of reaction

For a reaction $r=k[A][B]^2$, if concentration of $A$ is doubled the rate of reaction
  1. increases by 2
  2. decrease by $\frac{1}{2}$
  3. increases by 4
  4. decreases by 2

Solution

$\begin{aligned} & \text { Rate }=\mathrm{k}[\mathrm{~A}][\mathrm{B}]^2 \\ & (\text { Rate })_2=\mathrm{k}[2 \mathrm{~A}][\mathrm{B}]^2=\mathrm{k} \times 2[\mathrm{~A}][\mathrm{B}]^2 \\ \therefore \quad & (\text { Rate })_2=2 \times \text { Rate } \end{aligned}$ i.e., rate of reaction increases by a factor of 2 .

Asked in: MHT CET 2024 (15 May Shift 2)

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