Question

if we burn silk fibre , it gives a smell of burning hair . why ?

Answer 1

Silk fibre is obtained from silk worms,hence called as animal fibre.Silk fibre contains proteins such as sericine and fibrin.
So,when we burn silk fibre,we are burning proteins indirectly. So,when we burn silk fibre,it gives a smell of burning hair as hair also contains proteins.

Hope it helps

Answer 2

Silk is a type of protein. There are two types of protein in silks. They are: protein Fibroin which is seen in the silk and the protein keratin in the silk hair. It doesn't give the same strong odour of burning hair like in other fibers like wool. It produces a sulfurous odor. This is because the protein keratin in the hair contains large amounts of cysteine. So the smell of burnt silk fibre can cling to the nostrils for days.