Alkalies do not have a harmful effect on :

Question

Accepted Answer

Option 1, Cotton, is the correct answer because alkalies do not have a harmful effect on cotton fibers. Cotton is a natural cellulose fiber, and cellulose is resistant to alkaline substances. This resistance is due to the chemical structure of cellulose, which remains stable and does not degrade when exposed to alkaline conditions. In fact, cotton can be treated with alkaline solutions, such as sodium hydroxide, in a process called mercerization, which enhances its strength and luster.

Now, let's explain why the other options are incorrect:

2. Silk: Silk is a protein fiber, and proteins are sensitive to alkaline substances. Alkalies can break down the peptide bonds in proteins, leading to the degradation of silk fibers. This can result in a loss of strength and luster, making silk unsuitable for exposure to alkaline conditions.

3. Wool: Like silk, wool is also a protein fiber composed of keratin. Alkalies can damage the protein structure of wool, causing it to weaken and lose its natural properties. Wool fibers can become brittle and less elastic when exposed to alkaline substances, which is why they are not resistant to alkalies.

4. Rayon: Rayon is a semi-synthetic fiber made from regenerated cellulose. Although it is derived from cellulose, the manufacturing process alters its structure, making it more susceptible to damage from alkaline substances. Alkalies can cause rayon fibers to swell and weaken, leading to a loss of integrity and durability.

In summary, cotton is the only fiber among the options that is resistant to alkalies due to its natural cellulose composition, making Option 1 the correct answer.