Pennsylvania Cosmetology Practice Exam

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What is the MAIN ingredient in a chemical hair relaxer?

Sodium hydroxide
Guar gum
Keratin
Glycerin

The correct answer is: Sodium hydroxide

A chemical hair relaxer is a type of hair product that is used to chemically straighten curly or textured hair. The main ingredient in a chemical hair relaxer is sodium hydroxide, commonly known as lye. Sodium hydroxide works by breaking the disulfide bonds in the hair, which are responsible for the hair's natural texture. This allows the hair to be reshaped into a straighter form. Guar gum, keratin, and glycerin are also important ingredients in hair products, but they do not have the same chemical properties as sodium hydroxide and do not play a key role in the hair relaxing process. In fact, using these ingredients alone would not result in a straightening effect on the hair. Therefore, they are not the main ingredient in a chemical hair relaxer.