The correct answer is: A. sodium salts of fatty acids.
Detergents are anionic surfactants, which means they have a negatively charged end and a positively charged end. The negatively charged end of the detergent molecule is attracted to water, while the positively charged end is attracted to oil and grease. This allows detergents to break down and remove dirt and grime from surfaces.
Sodium salts of fatty acids are the most common type of detergent. They are made by reacting sodium hydroxide with a fatty acid, such as stearic acid or palmitic acid. The resulting product is a sodium salt of the fatty acid, which is a white, water-soluble solid.
Sodium salts of fatty acids are effective detergents because they are able to form micelles. Micelles are tiny, spherical structures that form when detergent molecules aggregate together. The hydrophobic (water-hating) tails of the detergent molecules point inward, while the hydrophilic (water-loving) heads point outward. This allows the micelles to surround and trap oil and grease, which can then be rinsed away with water.
Sodium salts of fatty acids are safe and effective detergents that are widely used in a variety of products, including laundry detergent, dishwashing detergent, and hand soap.
Option B is incorrect because sodium salts of sulphonic acids are not anionic surfactants. They are cationic surfactants, which means they have a positively charged end and a negatively charged end. Cationic surfactants are not as effective as anionic surfactants at removing dirt and grime from surfaces.
Option C is incorrect because sodium salts of benzoic acids are not surfactants. They are acids that are used as preservatives in food and cosmetics.
Option D is incorrect because sodium salts of fatty acids are the most common type of detergent.