70% alcohol on the hairstrand for 5-7mins can remove:

• A. Hydrogen peroxide
• B. Henna
• C. Water
• D. Acetone

Answer: (B)

Understanding how solvents interact with plant-based hair dyes helps explain why 70% alcohol can remove henna. Henna dyes the hair by depositing pigment molecules onto the outer layer of the hair shaft and forming bonds with the keratin. This makes the color relatively persistent and not easily rinsed away by plain water. A strong solvent like 70% alcohol can penetrate the cuticle and dissolve many of the surface dye molecules, so with several minutes of contact, enough pigment can be loosened and removed from the strand.

Hydrogen peroxide, by contrast, isn’t mainly a remover of dye. It oxidizes color, which can lighten or alter the shade, but it doesn’t dissolve and wash away the dye molecules the way a solvent does. Water isn’t effective either for henna removal because the dye’s attachment to the hair is resistant to simple rinsing. Acetone is a stronger solvent and could remove more dye or damage the hair, but it’s harsher and not the typical method used in this scenario.