For the reaction A → Products, the rate of reaction increases by a factor of 6.25 when the concentration of A is increased by a factor of 2.5. The order of the reaction with respect to A is:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 2
For A → Products the rate law is Rate = k[A]n, where n is the order with respect to A. Comparing the two rates, k cancels:
\( \displaystyle \frac{\text{Rate}_2}{\text{Rate}_1}=\left(\frac{[\ce{A}]_2}{[\ce{A}]_1}\right)^{n} \)
\( \displaystyle 6.25=(2.5)^{n} \)
\( \displaystyle (2.5)^2=6.25\quad\Rightarrow\quad n=2 \)
The reaction is second order in A.