One of the monomer of Nylon 6, 6 is an acid. How many `-COOH` groups are present in this acidic monomer.

Answer

To determine how many -COOH (carboxylic acid) groups are present in the acidic monomer of Nylon 6,6, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Monomers of Nylon 6,6**:
- Nylon 6,6 is a type of polyamide made from two different monomers: adipic acid and hexamethylenediamine.

2. **Identify the Structure of Adipic Acid**:
- Adipic acid is a dicarboxylic acid with the chemical formula C6H10O4. Its structure consists of a six-carbon chain with two -COOH groups at each end.

3. **Count the -COOH Groups**:
- In the structure of adipic acid, there are two -COOH groups. This means that for the acidic monomer (adipic acid), there are 2 carboxylic acid functional groups.

4. **Conclusion**:
- Therefore, the number of -COOH groups present in the acidic monomer (adipic acid) of Nylon 6,6 is 2.

### Final Answer:
The acidic monomer of Nylon 6,6 contains **2 -COOH groups**.

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