NIC Barber Written (Theory) ExamScientific ConceptsHard
A barber is performing a chemical hair relaxing service. The product label states it contains a 'reduction' agent to break the disulfide bonds in the hair. What chemical process is occurring when these bonds are broken to permanently alter the hair's curl pattern?
- AReduction
- BOxidation
- CNeutralization
- DHydrolysis
Show answer & explanationAnswer & explanation
Correct answer: A. Reduction
In chemical hair relaxing and perming, reduction is the process of breaking the disulfide bonds (S-S bonds) in the hair's cortex. This allows the hair to be reshaped. Oxidation then reforms these bonds in the new shape.
Why the other options are wrong
- B. Oxidation is the *reforming* of disulfide bonds, not the breaking.
- C. Neutralization balances pH, it doesn't directly break disulfide bonds for reshaping.
- D. Hydrolysis involves water breaking bonds, but reduction specifically refers to the chemical breaking of disulfide bonds by adding hydrogen or removing oxygen/electrons.
Reduction (Hair Chemistry)
A chemical reaction in hair services (like perming or relaxing) where disulfide bonds are broken by the addition of hydrogen atoms, allowing the hair to be reshaped.
- Breaks disulfide bonds (S-S bonds).
- Involves chemical reducing agents (e.g., thioglycolate).
- First step in permanent reshaping of hair.
Memory trick: Reduction Breaks Bonds, Oxidation Reforms Them.