The molecularity of a complex reaction is always greater than the order of the reaction. True or False

Answer

To determine whether the statement "The molecularity of a complex reaction is always greater than the order of the reaction" is true or false, we can analyze the concepts of molecularity and order of a reaction.

### Step-by-Step Solution:

1. **Define Molecularity**:
- Molecularity refers to the number of reactant molecules involved in an elementary reaction step. It is a theoretical concept and can only be a whole number (1, 2, 3, etc.).
- For example, in a reaction where 2 molecules of A react to form products, the molecularity is 2.

2. **Define Order of Reaction**:
- The order of a reaction is determined experimentally and refers to the sum of the powers of the concentration terms in the rate law expression.
- For example, if the rate law is given by \( \text{Rate} = k[A]^m[B]^n \), the order of the reaction is \( m + n \).

3. **Complex Reactions**:
- Complex reactions consist of multiple elementary steps. The overall order of the reaction is often determined by the slowest step, known as the rate-determining step.
- The rate law for the overall reaction is derived from this slow step.

4. **Comparison of Molecularity and Order**:
- In some cases, the molecularity of the rate-determining step can equal the order of the reaction. For example, if the slow step involves 2 molecules of A, the molecularity is 2, and if the rate law derived from this step is \( \text{Rate} = k[A]^2 \), the order is also 2.
- There are also cases where the molecularity can be greater than the order, especially in complex reactions involving intermediates or multiple steps.

5. **Conclusion**:
- Since there are instances where the molecularity equals the order, and not always greater, the statement "The molecularity of a complex reaction is always greater than the order of the reaction" is **False**.

### Final Answer:
**False**