Question

Which of the following statements regarding fibres are true?​
1. Fibroin is an insoluble protein present in silk.​
2. The process of scouring of wool involves the risk of getting infected by Anthrax bacteria.​
3. Wool melts on burning and gives an odour similar to that of burning paper.​
4. Cotton melts on burning and gives an odour similar to that of burning hair. ​
5. Polyester melts on burning and gives an odour similar to that of burning plastic.​

• A. 2, 3, and 4​
• B. 1, 3, and 5​
• C. 2, 3, and 5​
• D. 1, 2, and 5​

Answer 1

The correct option is D 1, 2, and 5​

• Fibroin is an insoluble protein present in silk.​ Hence, statement 1 is correct.
• In the wool industry, wool sorters can get infected by Anthrax bacteria which causes a fatal blood disease, called anthrax or sorter’s disease. Hence, statement 2 is correct.
• Animal fibres on burning give an odour similar to that of burning hair whereas, plant fibres on burning give an odour similar to that of burning paper. Also, natural fibres, that is, animal and plant fibres generally do not melt on burning. Since wool is an animal fibre, it does not melt on burning and gives an odour similar to that of burning hair. Hence, statement 3 is incorrect.
• Cotton is a plant fibre. So it does not melt on burning and gives an odour similar to burning paper. Hence, statement 4 is incorrect.
• Synthetic fibres such as polyester, on burning, generally melt and give an odour similar to that of burning plastic. So statement 5 is correct.
• Hence, only statements 1, 2 and 5 are correct. Therefore, the correct option is C.