When two immiscible solvents are mixed, two layers form. Liquid-liquid extractions commonly use organic solvents that are less dense than aqueous solutions, and therefore form the top layer. An important exception to this rule is chlorinated solvents, which are often more dense than aqueous solutions, and form the bottom layer. Suppose you were unsure which layer was which during your extraction. What simple method do think you could use to determine which of the two layers was the aqueous layer?