Question

Identify the correct statement from the following:

• A. Unbranched hydrocarbon detergents are non-biodegradable
• B. Cetyltrimethyl ammonium bromide is used in hair conditioners
• C. Liquid dish washing detergents are anionic type
• D. Synthetic detergents cannot be used in hard water

Hint:

Remember the different types of detergents (anionic, cationic, non-ionic) and their applications. Cationic surfactants are often used where a positive charge is beneficial, such as in hair conditioning. The biodegradability of detergents is improved with linear hydrocarbon chains. Synthetic detergents are advantageous over soaps in hard water.

Answer 1

The Correct Option is B

Step 1: Evaluate each statement. \begin{itemize} \item (1) Unbranched hydrocarbon detergents are non-biodegradable: Branched hydrocarbon detergents are less biodegradable due to the difficulty of microbial enzymes to break down the branched chains. Unbranched (linear) hydrocarbon detergents are generally biodegradable. So, this statement is incorrect. \item (2) Cetyltrimethyl ammonium bromide is used in hair conditioners: Cetyltrimethyl ammonium bromide (CTAB) is a cationic surfactant. Cationic surfactants are commonly used in hair conditioners because their positively charged head groups bind to the negatively charged surface of hair, reducing static electricity and providing a smooth feel. So, this statement is correct. \item (3) Liquid dish washing detergents are anionic type: While some liquid dishwashing detergents may contain anionic surfactants, many are non-ionic or a mixture of anionic and non-ionic surfactants to effectively remove grease and food particles and to be gentle on hands. Anionic surfactants like sodium lauryl sulfate (SDS) are common in laundry detergents. So, this statement is not universally true and likely incorrect as a general statement. \item (4) Synthetic detergents cannot be used in hard water: Synthetic detergents are designed to work well in hard water because their calcium and magnesium salts are soluble and do not form scum, unlike soaps. So, this statement is incorrect. \end{itemize}
Step 2: Identify the correct statement.
Based on the evaluation, the correct statement is (2). Final Answer: \[ \boxed{\text{Cetyltrimethyl ammonium bromide is used in hair conditioners}} \]