Texas Cosmetology Operator Written ExamChemistryMedium
When a cosmetologist mixes a permanent hair color with hydrogen peroxide, a chemical reaction occurs that allows the color to penetrate the hair shaft and develop. This type of chemical reaction, typically involving the transfer of electrons, is known as:
- ANeutralization reaction
- BHydrolysis reaction
- CPrecipitation reaction
- DOxidation-reduction reaction
Show answer & explanationAnswer & explanation
Correct answer: D. Oxidation-reduction reaction
Hair coloring involves an oxidation-reduction (redox) reaction. Hydrogen peroxide acts as an oxidizer, removing electrons from the color molecules, which then combine to form larger, permanent color molecules inside the hair shaft. The hair's natural pigment is also lightened through oxidation.
Why the other options are wrong
- A. A neutralization reaction occurs when an acid and a base react to form water and a salt.
- B. Hydrolysis is a reaction where water breaks down a compound into two or more other compounds.
- C. A precipitation reaction forms an insoluble solid (precipitate) from two soluble reactants.
Oxidation-Reduction (Redox) Reaction
A chemical reaction that involves the transfer of electrons between two species, where one species is oxidized (loses electrons) and another is reduced (gains electrons).
- Oxidation = loss of electrons
- Reduction = gain of electrons
- Crucial for hair coloring and perming
Memory trick: LEO says GER: Loss of Electrons is Oxidation, Gain of Electrons is Reduction.