70% alcohol on the hairstrand for 5-7mins can remove which substance?

• A. Dyes
• B. Henna
• C. Bleach
• D. Color glaze

Answer: (B)

This question tests how a common solvent interacts with different hair color substances. A 70% isopropyl alcohol soak is effective at dissolving or lifting surface pigments that aren’t firmly fixed inside the hair.

Henna is a plant-based dye that tends to coat the hair strand and bind more loosely to the outer layers than many synthetic dyes. With a few minutes of alcohol exposure, the surface pigment can be dissolved and drawn out, making henna more removable in this scenario.

In contrast, synthetic dyes form stronger bonds and can penetrate the hair, so a short alcohol soak won’t fully remove them. Bleach works by oxidizing color molecules rather than simply dissolving them, so alcohol wouldn’t remove the color created by bleaching. Color glaze is a surface film, and while solvents can affect films, the question emphasizes removing the pigment itself, where henna’s more superficial attachment makes it the best fit for removal by this alcohol treatment.