For the rate expression rate 3/2 k A B the overall order of a reaction is — Chemical Kinetics Chemistry Question

💡 Solution & Explanation

# Solution: Overall Order of Reaction **Given rate expression:** $$\text{rate} = k[A]^{3/2}[B]^1$$ **Step 1: Identify individual orders** - Order with respect to $[A]$ = $\frac{3}{2}$ - Order with respect to $[B]$ = $1$ **Step 2: Calculate overall order** The overall order is the sum of all individual orders: $$\text{Overall order} = \frac{3}{2} + 1 = \frac{3}{2} + \frac{2}{2} = \frac{5}{2} = 2.5$$ **Why this is correct:** The overall order determines how the total rate depends on concentration changes. Here, if all concentrations double, the rate increases by a factor of $2^{2.5} \approx 5.66$, which validates the fractional exponent. **Note:** The overall order is **2.5** (or **5/2**), which is a fractional order—commonly seen in multi-step reactions where the rate-determining step involves fractional stoichiometry.