Question

The gas used in gas delinting of cotton seeds is-

• A. Dry $CO_2$
• B. Nitric oxide
• C. Sulphur di-oxide
• D. Dry hydrochloric acid

Hint:

Associate "Dry Delinting" with HCl gas and "Wet Delinting" with Sulphuric Acid ($H_2SO_4$).
Delinting also helps in detecting "pink bollworm" infestation and improves germination percentage.

Answer 1

The Correct Option is D

Step 1: Understanding the Question:
The question asks for the specific chemical agent used in the "gas delinting" process for cotton seeds.
Delinting is a post-harvest process essential for making cotton seeds suitable for mechanical sowing and seed treatment.

Step 2: Detailed Explanation:

• What is Delinting? Cotton seeds are naturally covered with short fibers called "linters" or "fuzz".

• These linters prevent seeds from flowing freely in seed drills and make seed treatment difficult.

• Methods of Delinting:
• Mechanical: Scraping the fuzz off (often incomplete).

• Acid Delinting (Wet): Using concentrated sulphuric acid.

• Gas Delinting (Dry): Using anhydrous (dry) Hydrochloric Acid ($HCl$) gas.

• Mechanism of Gas Delinting: Seeds are exposed to $HCl$ gas in a rotating drum.

• The gas reacts with the cellulose in the linters, making them brittle.

• These brittle linters are then easily rubbed off or removed by air blasts.

• Advantages: It is faster than wet acid delinting and significantly reduces the risk of seed damage or environmental pollution from liquid acid waste.
Final Answer:
Dry hydrochloric acid gas is the standard agent used in the gas delinting of cotton seeds to remove the fuzz effectively.