Question

Paheli went to the market to buy sarees for her mother. She took out a thread from the edge of the two sarees shown by the shopkeeper and burnt them. One thread burnt with a smell of burning hair and the other burnt with the smell of burning paper. Which thread is from a pure cotton saree and which one from a pure silk saree? Give reason for your answer.

Answer 1

To identify the purity of silk, you have to burn a thread of silk. If the burning smell of that thread is similar to burning smell of hair then the thread will be a pure silk. Silk and hairs are protein fibres, thus, they generate same smell.
To identify the purity of cotton, you have to burn a thread of cotton. If the burning smell of that thread is similar to burning smell of paper then the thread will be pure cotton. Cotton and paper are carbohydrates, thus, they generate same smell.