What is an acid rinse with a pH of 2-3 designed to do?

An acid rinse with a pH of 2-3 is primarily designed to help dissolve soap scum and other alkaline residues on hair and scalp. The low pH of the rinse effectively neutralizes the alkalinity present in many cleansing products, which can leave behind build-up. This neutralization helps to remove soap scum, hard water deposits, and other impurities that can accumulate on the hair.

In contrast, while an acid rinse may contribute to a healthier overall appearance of the hair, it is not used mainly for adding moisture, coloring, or strengthening the hair. Those functions are generally associated with conditioners or specialized treatments rather than a simple rinse. Thus, choosing the option related to dissolving soap scum aligns perfectly with the intended use of an acid rinse.