Structurally biodegradable detergent should contain :

Options

A. Normal alkyl chain
B. Branched alkyl chain
C. Alkyl side chain
D. Cyclohexyl side chain

Answer

To determine which type of chain a structurally biodegradable detergent should contain, we need to analyze the options provided and understand the concept of biodegradability in detergents.

### Step-by-Step Solution:

1. **Understand Biodegradable Detergents**:
- Biodegradable detergents are those that can be broken down by microorganisms, such as bacteria, into simpler, non-toxic substances. This is important for environmental sustainability.

2. **Analyze the Options**:
- **Normal Alkyl Chain**: This refers to a straight-chain hydrocarbon. These chains are typically easier for bacteria to metabolize because they lack complex branching or substituents.
- **Branched Alkyl Chain**: These chains have branches off the main carbon chain. The presence of branches can hinder the ability of bacteria to break down the molecule efficiently.
- **Alkyl Side Chain**: This term generally refers to an alkyl group that is attached as a side chain. Similar to branched chains, side chains can complicate the structure and make it harder for bacteria to decompose.
- **Cyclohexyl Side Chain**: This refers to a cyclic structure. Cyclic compounds are often more stable and can be more resistant to biodegradation due to their structure.

3. **Conclusion**:
- Based on the analysis, the normal alkyl chain is the most suitable option for a structurally biodegradable detergent because it is a straight chain that can be easily attacked and broken down by bacteria. The other options, due to their complexity and branching, would likely hinder biodegradation.

### Final Answer:
The structurally biodegradable detergent should contain **normal alkyl chain** (Option A).

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