Question

Which of the following is cationic detergent?

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

Answer 1

The Correct Option is C

The question asks which of the following substances is a cationic detergent. Let's evaluate each option to understand their properties:

1. Sodium lauryl sulphate: This is an anionic detergent. It has a negatively charged sulfate head (SO₄^-) which interacts with water, making it an effective cleaning agent.
2. Sodium stearate: This is also an anionic detergent commonly used in the manufacture of soaps. It has a negatively charged carboxylate group (COO^-).
3. Cetryltrimethyl ammonium bromide: This compound is a cationic detergent. It carries a positive charge on the nitrogen atom (N⁺) of the ammonium group. The positive charge makes it specifically useful in applications such as fabric softeners and hair conditioners where interaction with negatively charged surfaces is desirable.
4. Sodium dodecylbenzene sulphonate: This is another anionic detergent often used in laundry and dishwashing detergents due to its sulfonate group (SO₃^-).

From the above analysis, we can conclude that the correct answer is Cetryltrimethyl ammonium bromide as it is the only cationic detergent among the given options. Cationic detergents possess a positively charged part which typically involves a quaternary ammonium group.