Question

soaps feel slippery on our hands because they dissolve the oil on our skin, decreasing friction. this is because soap contains
○ a neutral molecule.
○ a salt molecule.
○ an acid.
○ a base.

Explanation:

Soaps are formed from the saponification reaction of fats/oils (triglycerides) with a strong base (like NaOH or KOH). Bases react with fats to form soap molecules which have both polar and non - polar parts, allowing them to dissolve oil (non - polar) and interact with water (polar). Neutral molecules don't have the dual - nature to dissolve oil and reduce friction in this way. Soap is not a salt molecule in the context of this question (it's a salt of a fatty acid, but the key property here is due to its basic origin and nature of interaction with oil), and acids do not react with fats to form soap in the way that bases do, and acids also don't have the right properties to dissolve oil on skin to reduce friction like soap does.

Answer:

D. a base