Final answer:
A 20 volume hydrogen peroxide solution is a hair bleaching agent that decomposes to produce oxygen, which lightens hair by reacting with melanin. While lower concentrations are used as disinfectants, a 20 volume solution is more concentrated and effective for cosmetic hair treatments.
Step-by-step explanation:
A 20 volume hydrogen peroxide solution refers to a mixture that can release 20 times its volume in oxygen at standard temperature and pressure. When used in hair bleaching, this concentration of hydrogen peroxide effectively lifts the natural hair color, thus lightening it. The process involves the decomposition of hydrogen peroxide which produces a high amount of oxygen that reacts with the melanin in hair, reducing the melanin's pigment and resulting in a bleached or lighter appearance.
While 3% solutions are commonly utilized as disinfectants, diluted hydrogen peroxide mixed with aqueous ammonia is often used for bleaching hair. In advanced hair treatments such as perms, an oxidizing agent like a dilute hydrogen peroxide solution is used for breaking and reforming the disulfide bonds in the hair. For safety and efficacy in cosmetic applications, it is essential to use the appropriate volume and concentration, as higher concentrations are reserved for antiseptic and sterilization purposes, which require more caution due to their increased reactivity and potential for causing damage.