Final answer:
The second ingredient in most shampoos is the surfactant, which contains the surface active cleaning agents. Shampoo is made by combining a surfactant with a co-surfactant in water.
Step-by-step explanation:
The second ingredient listed in most shampoos is the surfactant, or base detergent, which contains the surface active cleaning agents. Shampoo is generally made by combining a surfactant, most often sodium lauryl sulfate or sodium laureth sulfate, with a co-surfactant, most often cocamidopropyl betaine in water to form a thick, viscous liquid. Other essential ingredients include salt (sodium chloride), which is used to adjust the viscosity, a preservative and fragrance.