Pick the correct statement among the following :

Options

A. Sodium dodecylbenzene sulphonate used in tooth paste is cationic detergetn .
B. Sodium lauryl sulphate forms an insoluble scum with hard water.
C. Cetyltrimethyl ammonium bromide is a popular cationic detergent used in hair conditioners .
D. Non - ionic detergents are formed when polyethylene glycol reacts with adipic acid .

Answer

To solve the question, we need to analyze each statement provided and determine which one is correct.

### Step-by-Step Solution:

1. **Evaluate the First Statement:**
- The statement claims that "Sodium dodecylbenzene sulfonate is used in toothpaste and is a cationic detergent."
- To evaluate this, we need to understand the nature of sodium dodecylbenzene sulfonate. It is known to be an anionic detergent, not a cationic one. Anionic detergents carry a negative charge, while cationic detergents carry a positive charge.
- **Conclusion:** This statement is incorrect.

2. **Evaluate the Second Statement:**
- The statement claims that "Sodium lauryl sulfate forms an insoluble scum with hard water."
- Sodium lauryl sulfate is a common anionic detergent. When it comes into contact with hard water (which contains calcium and magnesium ions), it can form soluble complexes rather than insoluble scum due to the presence of builders in the detergent.
- **Conclusion:** This statement is also incorrect.

3. **Evaluate the Third Statement:**
- The statement claims that "Cetyltrimethylammonium bromide is a popular cationic detergent used in hair conditioners."
- Cetyltrimethylammonium bromide is indeed a cationic detergent and is widely used in hair conditioners for its conditioning properties.
- **Conclusion:** This statement is correct.

4. **Evaluate the Fourth Statement:**
- The statement claims that "Non-ionic detergents are formed when polyethylene glycol reacts with stearic acid."
- Non-ionic detergents can be formed from the reaction of polyethylene glycol with fatty acids like stearic acid, resulting in a non-ionic surfactant.
- **Conclusion:** This statement is also correct.

### Final Answer:
The correct statement among the options provided is:
- **Cetyltrimethylammonium bromide is a popular cationic detergent used in hair conditioners.** (Option C)