Find out number of reactions which involve electron deficient
nitrogen during reaction mechanism.
`CH_(3) - overset(overset(O)(||))C - Cl underset(H_(2)O) overset(NaN_3) (to)`

Explanation

To solve the question, we need to analyze the reaction of the acid chloride with sodium azide (NaN₃) and identify the steps that involve electron-deficient nitrogen.

### Step-by-Step Solution:

1. **Identify the Reactants**:
The reactants in this reaction are an acid chloride (in this case, CH₃C(=O)Cl) and sodium azide (NaN₃).

2. **Understand the Structure of Sodium Azide**:
Sodium azide consists of the azide ion (N₃⁻), which has a linear structure: N⁺≡N⁻—N⁻. The terminal nitrogen atoms (N⁻) are electron-rich, while the central nitrogen (N⁺) is electron-deficient.

3. **Reaction Mechanism**:
When the acid chloride reacts with sodium azide, the nucleophilic azide ion attacks the carbonyl carbon of the acid chloride. The mechanism involves the following steps:
- The electron-rich nitrogen (N⁻) from the azide attacks the electrophilic carbon of the acid chloride.
- This leads to the formation of a tetrahedral intermediate, which then collapses, expelling chloride ion (Cl⁻) and forming an azide compound.

4. **Formation of Electron-Deficient Nitrogen**:
In the process, the nitrogen that was part of the azide ion becomes involved in the formation of the new bond with the carbon atom of the acid chloride. The central nitrogen (N⁺) in the azide ion is electron-deficient and plays a crucial role in this reaction.

5. **Count the Reactions Involving Electron-Deficient Nitrogen**:
- The initial attack of the azide ion involves the electron-deficient nitrogen.
- The rearrangement that occurs after the formation of the tetrahedral intermediate also involves this nitrogen.
- Therefore, we can conclude that there are at least two significant steps in the reaction mechanism that involve the electron-deficient nitrogen.

### Conclusion:
The number of reactions that involve electron-deficient nitrogen during the reaction mechanism is **2**.

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