Question

Glauber's salt (Na₂SO₄·10H₂O) is used as a .......... agent with acid dyes.

• A. Oxidising
• B. Adding
• C. Subtracting
• D. Levelling

Hint:

Levelling agents control the rate of dye uptake, ensuring even shade distribution on textiles.

Answer 1

The Correct Option is D

Step 1: Understand the role of Glauber’s salt.
Glauber’s salt is sodium sulphate decahydrate (Na₂SO₄·10H₂O). It is a common inorganic salt used in the dyeing industry, especially in dye baths with acid dyes and direct dyes.
Step 2: Levelling agent function.
The primary purpose of Glauber’s salt is to act as a levelling agent. A levelling agent ensures that the dye molecules are distributed evenly throughout the fabric, avoiding patchy or uneven dyeing. It slows down the dye absorption by the fiber so that the dye can penetrate more uniformly.
Step 3: Why other options are wrong.
- Oxidising: Glauber’s salt does not oxidize dyes or fibers.
- Adding: This is not a technical term related to dyeing auxiliaries.
- Subtracting: Also not a dyeing-related role.
Only “Levelling” is correct.
Step 4: Conclusion.
Thus, Glauber’s salt acts as a levelling agent in dyeing with acid dyes.