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xiii. What is zeroth order reaction? Derive its integrated rate law. What are the units of rate constant

**chapter 6. CHEMICAL KINETICS class 12 chemistry textbook solution**

### 3. Answer the following in brief.

xiii. What is zeroth order reaction? Derive its integrated rate law. What are the units of rate constant?

**chapter 6. CHEMICAL KINETICS class 12 chemistry textbook solution page 137**

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- xiii. What is zeroth order reaction? Derive its integrated rate law. What are the units of rate constant

**Answer:- **Reactions in which the rate is independent of the reactant concentration are zeroth-order reaction.

**The integrated rate law for zero-order reactions:**

For a zero-order reaction, A → P, the differential rate law is given by:

rate = \(-\frac{d[A]}{[A]} = k[A]_0 = k \quad \text{(1)}\)

Rearranging Equation (1) gives:

\(d[A] = -k dt \quad (\because [A]^0 = 1)\)

Integration between the limits:

\([A] = [A]_0\) at \(t = 0\) and \([A] = [A]_t\) at \(t = t\) gives:

\(\int_{[A]_0}^{[A]_t} d[A] = -k \int_{0}^{t} dt\)

\([A]_t - [A]_0 = -kt\)

Hence, \(kt = [A]_0 - [A]_t \quad (2)\)

The unit of the rate constant for the zero-order reaction is mol dm-3 s-1.