Define Elementary step in a reaction

Answer

**Step-by-Step Solution:**

1. **Understanding the Reaction**: In any chemical reaction, we start with reactants that undergo a transformation to form products. This process is what we refer to as a chemical reaction.

2. **Defining Elementary Step**: An elementary step in a reaction is a single step process where the reactants convert directly into products without any intermediate stages.

3. **Characteristics of Elementary Steps**:
- An elementary step involves a direct transformation of reactants to products.
- It occurs in one single molecular event.
- The rate of an elementary reaction can be directly related to the molecularity of the reaction.

4. **Example of an Elementary Step**: Consider the reaction between nitrogen gas (N2) and oxygen gas (O2) to form nitrogen monoxide (NO). The reaction can be represented as:
\[ N_2(g) + O_2(g) \rightarrow 2 NO(g) \]
This reaction occurs in a single step, making it an elementary reaction.

5. **Conclusion**: Thus, an elementary step is defined as a reaction that occurs in a single step without any intermediates, and it can be represented by a simple chemical equation.

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