Which ingredient is found in the stronger of the two most commonly used chemical hair relaxers?

• A. Ammonium thioglycolate
• B. Sodium hydroxide (NaOH)
• C. Hydrogen peroxide (H2O2)
• D. Calcium hydroxide (Ca(OH)2)

Answer: (B)

Verified step by step guidance

1. Understand that chemical hair relaxers work by breaking the disulfide bonds in hair proteins, which changes the hair's structure and texture.
2. Recognize that the two most commonly used types of hair relaxers are 'lye' relaxers and 'no-lye' relaxers. Lye relaxers contain sodium hydroxide (NaOH), while no-lye relaxers often contain calcium hydroxide (Ca(OH)2) combined with other ingredients.
3. Know that sodium hydroxide (NaOH) is a strong base and is more potent in breaking down hair proteins compared to calcium hydroxide, which is milder.
4. Ammonium thioglycolate is used in 'perm' solutions to break disulfide bonds temporarily, not typically in hair relaxers, and hydrogen peroxide (H2O2) is an oxidizing agent used in hair bleaching, not relaxing.
5. Therefore, the ingredient found in the stronger of the two most commonly used chemical hair relaxers is sodium hydroxide (NaOH), due to its high alkalinity and effectiveness in permanently altering hair structure.