For a chemical reaction:
A + B → Products
| Experiment | \(\frac{[A]}{mol L^{-1}}\) | \(\frac{[B]}{mol L^{-1}}\) | \(\frac{\text{Initial rate}}{mol L^{-1} s^{-1}}\) |
| 1. | 0.1 | 0.1 | 2.0 x 10-3 |
| 2. | 0.2 | 0.2 | 4.0 x 10-3 |
| 3. | 0.1 | 0.2 | 2.0x 10-3 |
What is the overall order of chemical reaction?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → 1
Let rate = k[A]x[B]y.
Order in B (experiments 1 and 3, [A] fixed, [B] doubled):
\( \displaystyle \frac{2.0\times10^{-3}}{2.0\times10^{-3}} = \left(\frac{0.2}{0.1}\right)^y \Rightarrow 1 = 2^y \Rightarrow y = 0 \)
Order in A (experiments 1 and 2, both doubled):
\( \displaystyle \frac{4.0\times10^{-3}}{2.0\times10^{-3}} = 2^x \times 2^0 \Rightarrow 2 = 2^x \Rightarrow x = 1 \)
Order of the reaction = x + y = 1 + 0 = 1.