Identify the order of the two reactions whose rate constants are given below:

(i) $k = 2.3 × 10^{-5}\, L\, mol\,^{-1} s^{-1}$
(ii) $k= 3 × 10^{-4} s^{-1}$

(i) Second order, (ii) First order

The correct answer is Option (2) → (i) Second order, (ii) First order

The order of a reaction can be identified from the units of the rate constant (k).

• Second-order reaction:
  k has units of L mol⁻¹ s⁻¹
• First-order reaction:
  k has units of s⁻¹

Now, given:

1. (i) $k = 2.3 \times 10^{-5}\ \text{L mol}^{-1}\text{s}^{-1}$
   → Second-order reaction
2. (ii) $k = 3 \times 10^{-4}\ \text{s}^{-1}$
   → First-order reaction