The rate constant for a reaction is $3.5\, mol^{-1}\, L\, s^{-1}$. The order of the reaction is:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → Second
The units of the rate constant (k) depend on the order of the reaction (n):
$\text{Units of } k = \text{(concentration)}^{1-n} \cdot \text{time}^{-1}$
Given:
- $k = 3.5\ \mathrm{mol^{-1} L s^{-1}}$
Compare with the general unit formula:
- Zero order: $\text{mol L}^{-1} \text{s}^{-1}$ INCORRECT
- First order: $\text{s}^{-1}$ INCORRECT
- Second order: $\text{L mol}^{-1} \text{s}^{-1}$ --CORRECT
- Third order: $\text{L}^2 \text{mol}^{-2} \text{s}^{-1}$ INCORRECT