Q. An insoluble dye is reduced to a soluble colourless leuco form by an alkaline reducing agent. The fibre is soaked in the dye solution and then exposed to air to develop the colour. The dye is
A) Mordant dye
B) Vat dye
C) Azo dye
D) Direct dye
Explanation
(b)
Vat dyes are soluble in water and cannot directly applied. It is reduced to soluble colourless leuco form by an alkaline reducing agent. E.g.,
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Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.