Question 1

Why must a stylist base the scalp before applying a sodium hydroxide relaxer?

Accepted Answer

Sodium hydroxide (lye) relaxers have a pH of 12–14, making them highly caustic; applying a petroleum-based basing cream protects the scalp and skin from chemical burns during processing.

Question 2

What is the critical rule regarding applying a sodium hydroxide relaxer to hair that has already been relaxed?

Accepted Answer

A relaxer must never be overlapped onto previously relaxed hair; it should be applied only to the new growth to prevent over-processing, severe breakage, and irreversible cortex damage.

Question 3

What is the difference between an ammonium thioglycolate relaxer and a sodium hydroxide relaxer in terms of pH and scalp preparation?

Accepted Answer

Ammonium thioglycolate (thio) relaxers operate at pH 9–10 and require pre-shampooing before application; sodium hydroxide relaxers are stronger at pH 12–14 and must never be pre-shampooed.

Question 4

A client arrives for a relaxer retouch and admits she used a no-lye home relaxer six weeks ago. Why must you identify which relaxer system was used previously?

Accepted Answer

Mixing lye and no-lye relaxer systems can cause a chemical reaction that leads to extreme breakage and scalp burns; identifying prior chemical use ensures compatible products are selected.

Question 5

What chemical is the primary active ingredient in an alkaline cold wave perm, and at what pH does it process?

Accepted Answer

Alkaline cold wave perms use ammonium thioglycolate as the active ingredient, processing at a pH of 9.0–9.6 at room temperature to break and reform disulfide bonds into a new curl pattern.

NIC Cosmetology Exam: Chemical Services

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