Which is used for the formation of nylon-66 ?

Options

A. Sulphur hexafluoride
B. Adipic acid
C. Sulphurous acid
D. Phthalilc acid

Answer

To determine which compounds are used for the formation of nylon-66, we need to identify the monomeric units involved in its synthesis. Nylon-66 is a type of polyamide, and its formation involves a specific condensation polymerization reaction.

### Step-by-Step Solution:

1. **Identify the Monomers**:
- Nylon-66 is formed from two specific monomers: adipic acid and hexamethylenediamine.
- Adipic acid has the formula:
\[ HOOC-(CH_2)_4-COOH \]
- Hexamethylenediamine has the formula:
\[ H_2N-(CH_2)_6-NH_2 \]

2. **Understand the Reaction**:
- The formation of nylon-66 involves a condensation reaction between adipic acid and hexamethylenediamine.
- During this reaction, water (H2O) is eliminated as a byproduct, and an amide linkage is formed.

3. **Write the Reaction**:
- The reaction can be represented as follows:
\[ n \times (HOOC-(CH_2)_4-COOH) + n \times (H_2N-(CH_2)_6-NH_2) \rightarrow [-NH-(CH_2)_6-NH-CO-(CH_2)_4-CO-]_n + nH_2O \]
- Here, the repeating unit of nylon-66 is formed through the amide linkage.

4. **Conclusion**:
- The two compounds used for the formation of nylon-66 are adipic acid and hexamethylenediamine. Therefore, the correct answer to the question is adipic acid.

### Final Answer:
Adipic acid and hexamethylenediamine are used for the formation of nylon-66.

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