Which facial treatment involves the use of a chemical solution to exfoliate the skin?

The correct answer is the chemical peel, which specifically utilizes a chemical solution to exfoliate the skin. This process involves applying various acids or enzymes to the skin, which helps in removing the outer layers of dead skin cells. The depth of the exfoliation can vary based on the type and strength of the chemical used, and this treatment is often used to improve the appearance of skin by addressing issues such as fine lines, sun damage, acne scars, and uneven skin tone.

Microdermabrasion, another skin treatment, uses a mechanical method to exfoliate the skin by gently abrading it with fine crystals or a diamond-tipped wand. While effective for a different type of exfoliation, it does not involve the use of chemical solutions.

A facial scrub typically involves the physical exfoliation of the skin using granular substances, which is a more manual process rather than a chemical one.

Steam treatment, on the other hand, is used primarily to open up the pores and hydrate the skin, but it does not involve exfoliation through the use of chemicals. Therefore, the chemical peel is the only option that directly matches the description of a facial treatment that employs a chemical solution for exfoliation.