NIC Barber Written (Theory) ExamScientific ConceptsMedium
A barber is preparing a non-foaming chemical depilatory for a client's neck shave. The product label states it contains a strong alkaline ingredient to break down hair proteins. What pH range would you expect this product to fall within?
- A5.0 - 6.5
- B2.0 - 4.0
- C7.0 - 8.5
- D10.0 - 12.0
Show answer & explanationAnswer & explanation
Correct answer: D. 10.0 - 12.0
Strong alkaline substances, like those found in chemical depilatories, have a high pH. They are designed to swell the hair and break disulfide bonds, requiring a pH typically in the 10.0-12.0 range to be effective.
Why the other options are wrong
- A. This is the acidic to slightly acidic range, common for hair and skin, but not strong enough for depilatories.
- B. This is a highly acidic range, which would contract the hair and not break down proteins effectively for depilation.
- C. This is neutral to mildly alkaline, insufficient for the strong action required to break down hair in a depilatory.
Alkaline pH
A measure of acidity or alkalinity where solutions have a pH greater than 7.
- Strongly alkaline solutions (pH 10+) swell hair and can break disulfide bonds.
- Used in chemical depilatories and relaxers.
- Can be damaging if used incorrectly due to high reactivity.
Memory trick: Alkaline attacks hair's bonds.