While using iodine in the laboratory, some drops of iodine fell on Paheli’s socks and some fell on her teacher 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?

The saree of Paheli’s teacher would have contained starch. When starch is exposed to iodine solution, starch turns into blue black so the saree also turned blue- black. Paheli’s socks would have not contained starch thus did not show any colour change.