Hydrogen bonds are easily broken by water or heat and are re-formed when the hair is which state?

• A. Dry
• B. Wet
• C. Colored
• D. Heated

Answer: (A)

Hydrogen bonds in hair are temporary attractions between adjacent keratin chains. They are easily broken by water or heat and re-form when the hair returns to a dry state. When hair dries, water leaves and the temperature cools, allowing those bonds to reform and the hair to regain its natural shape. So, the reformation happens in dry hair. Wet hair has these bonds broken, and while heat can break them as well, they come back as the hair dries. Coloring doesn’t directly determine the reformation state, and although heat can disrupt them, the restoring condition is dry hair.