Question

The dyes used in reduced state and are then oxidized in the fabric by air are called:

• A. azo dye
• B. vat dye
• C. basic dye
• D. dispersed dye

Answer 1

The correct option is B vat dye

Vat dyes can applied directly on fibre and are generally insoluble in water. These can be used only on cotton but can not be used on silk and wool. In this case dying is a continuous process and is carried out in a large vessel called vat. For this reason these dyes are Known as vat dyes, indigo is an example of vat dyes