Find out number of reactions which involve electron deficient
nitrogen during reaction mechanism.
`Ph - overset(overset(O)(||))C - OH overset(N_(3) H,"Dilute" H_(2) SO_(4) ) (to)`

Explanation

To solve the question regarding the number of reactions that involve electron-deficient nitrogen during the reaction mechanism, we can break down the process step by step.

### Step-by-Step Solution:

1. **Identify the Reactants**:
The given reactants are benzoic acid (Ph-C(=O)OH) and hydrazoic acid (N₃H) in the presence of dilute sulfuric acid (H₂SO₄).

**Hint**: Look for the functional groups in the reactants that will participate in the reaction.

2. **Understand the Reaction Type**:
The reaction described is a type of Schmidt reaction, which typically involves the conversion of carboxylic acids to amines using hydrazoic acid.

**Hint**: Recall what a Schmidt reaction entails and how it transforms carboxylic acids.

3. **Analyze the Role of Nitrogen**:
In hydrazoic acid (N₃H), the nitrogen atom is electron-deficient due to the presence of a positive charge on one of the nitrogen atoms in the azide group (N₃). This electron deficiency allows it to act as a nucleophile in the reaction.

**Hint**: Consider the structure of hydrazoic acid and how the nitrogen atoms are arranged.

4. **Reaction Mechanism**:
When benzoic acid reacts with hydrazoic acid in the presence of dilute H₂SO₄, the electron-deficient nitrogen can attack the carbonyl carbon of the benzoic acid, leading to the formation of an intermediate. This intermediate can then undergo further transformations to yield an amine product (aniline).

**Hint**: Visualize the mechanism step-by-step, focusing on how the nitrogen attacks the carbonyl carbon.

5. **Product Formation**:
The final product of this reaction is aniline (Ph-NH₂), which confirms that the electron-deficient nitrogen from hydrazoic acid was indeed involved in the reaction mechanism.

**Hint**: Think about the final structure of the product and how it relates to the starting materials.

### Conclusion:
In this reaction, we can conclude that there is one significant reaction that involves electron-deficient nitrogen, which is the conversion of benzoic acid to aniline through the Schmidt reaction.

### Final Answer:
**Number of reactions involving electron-deficient nitrogen: 1**