Which of the following is a cationic detergent?

Options

A. Sodium lauryl sulphate
B. Sodium stearate
C. Cetyltrimethyl ammonium bromide
D. Sodium dodecylbenzene sulphonate

Answer

To determine which of the following options is a cationic detergent, we need to understand the characteristics of cationic detergents and analyze the given options accordingly.

### Step-by-Step Solution:

1. **Definition of Cationic Detergent**:
- A cationic detergent is a type of detergent that carries a positive charge. It is typically a quaternary ammonium salt, which means it has a nitrogen atom bonded to four groups (alkyl or aryl groups) and carries a positive charge.

2. **Characteristics of Quaternary Ammonium Salts**:
- Quaternary ammonium salts are formed when a nitrogen atom is bonded to four carbon-containing groups. This nitrogen atom will have a positive charge because it can only form three covalent bonds with other atoms, leaving it with a positive charge when it is bonded to a fourth group.

3. **Analyzing the Options**:
- We need to evaluate each of the given options to see if they fit the criteria of a cationic detergent.

- **Option 1: Sodium lauryl sulfate**:
- This is an anionic detergent because it contains a sodium ion and a sulfate group, which is negatively charged. Thus, it is not a cationic detergent.

- **Option 2: Cetyl trimethyl ammonium bromide**:
- This compound has a quaternary ammonium structure with a nitrogen atom bonded to three methyl groups and one cetyl group (a long hydrocarbon chain). The nitrogen carries a positive charge, making this a cationic detergent.

- **Option 3: Another option (not specified)**:
- Without specific details, we cannot evaluate this option, but if it does not have a quaternary ammonium structure, it is likely not a cationic detergent.

- **Option 4: Another sodium-based compound**:
- Similar to option 1, if this compound contains sodium and does not have a quaternary ammonium structure, it is not a cationic detergent.

4. **Conclusion**:
- Based on the analysis, the only option that qualifies as a cationic detergent is **Option 2: Cetyl trimethyl ammonium bromide**.

### Final Answer:
**Cetyl trimethyl ammonium bromide** is the cationic detergent among the given options.

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