Question

Which type of dye forms a covalent bond with the fiber?

• A. Direct Dye
• B. Reactive Dye
• C. Vat Dye
• D. Disperse Dye

Hint:

{Reactive dyes} are widely used for cotton and other natural fibers because they form a strong {covalent bond}, giving excellent color fastness.

Answer 1

The Correct Option is B

Concept: Dyes are substances used to impart color to fibers, fabrics, or textiles. Different types of dyes interact with fibers in different ways. Reactive dyes are unique because they form a strong covalent bond with the fiber, which makes the color more durable and resistant to washing.
Step 1: Understand Reactive Dyes.
Reactive dyes chemically react with the functional groups present in fibers such as cotton, wool, or silk. During the dyeing process:

• The dye molecule reacts with the fiber.
• A covalent bond is formed between the dye and the fiber.

This chemical bonding makes the color highly stable.
Step 2: Compare with other dyes.

• Direct Dyes – Attach to fibers through physical attraction.
• Vat Dyes – Require chemical reduction before dyeing.
• Disperse Dyes – Mainly used for synthetic fibers like polyester.

Step 3: Conclusion.
Since reactive dyes form a covalent chemical bond with the fiber, the correct answer is: \[ \text{Reactive Dye} \]