Question

While using iodine in the laboratory, some drops of iodine fell on Paheli's socks and some fell on her teacher's saree. The drops of iodine on the saree turned blue-black while their colour did not change on the socks. What can be the possible reason?

Answer 1

The drops of iodine are used to detect the presence of starch, the appearance of blue-black colour. The possible reason for blue-black colour on teacher's saree could be the presence of starch. The saree might have been starched. Paheli's socks did not have starch on it, therefore the colour did not change.