The product formed by the reaction of an aldehyde with a primary amine is:

Options

A. ketone
B. Carboxylic acid
C. Aromatic acid
D. Schiff base

Explanation

To determine the product formed by the reaction of an aldehyde with a primary amine, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Reactants**:
We have an aldehyde, which can be represented as \( RCHO \), where \( R \) is an alkyl group (like methyl, ethyl, etc.). The primary amine can be represented as \( R'NH_2 \), where \( R' \) is also an alkyl group.

2. **Nucleophilic Attack**:
The nitrogen atom in the primary amine has a lone pair of electrons, making it nucleophilic. The carbon atom in the aldehyde is electrophilic due to the presence of the carbonyl group (C=O). The lone pair on nitrogen attacks the electrophilic carbon of the aldehyde:
\[ RCHO + R'NH_2 \rightarrow RCH(OH)(NH_2R')^+ \]

3. **Formation of a Tetrahedral Intermediate**:
This reaction forms a tetrahedral intermediate where the carbon atom is bonded to the hydroxyl group (OH) and the amine group (NH2). As a result, the nitrogen atom temporarily carries a positive charge because it now has four bonds.

4. **Proton Transfer**:
The hydroxyl group (OH) is not a stable group in this context. A proton transfer occurs from the nitrogen to the oxygen, leading to the formation of a better leaving group (water):
\[ RCH(OH)(NH_2R')^+ \rightarrow RCH(OH_2^+)(NH_2R') \]

5. **Elimination of Water**:
The positively charged hydroxyl group (now water) leaves, resulting in the formation of a double bond between the carbon and nitrogen:
\[ RCH(=NHR') + H_2O \]

6. **Formation of Schiff's Base**:
The final product is a compound known as a Schiff's base, which can be represented as:
\[ RCH=NR' \]
Here, \( RCH=NR' \) is the Schiff's base formed from the reaction of the aldehyde with the primary amine.

### Conclusion:
The product formed by the reaction of an aldehyde with a primary amine is a **Schiff's base**.