A chemistry class is experimenting with iodine to see which common white powder items will react and make the iodine change color. Which item listed will have a chemical reaction with iodine?

Question

powdered sugar

cornstarch

baking soda

salt

Answer 1

Among the items listed, cornstarch will have a chemical reaction with iodine. When iodine is added to cornstarch, it forms a blue-black complex, which is a classic demonstration of the starch-iodine reaction.

The other items do not produce a significant color change when iodine is added:

• Powdered sugar (sucrose) does not react with iodine.
• Baking soda (sodium bicarbonate) does not have a notable reaction with iodine.
• Salt (sodium chloride) also does not react with iodine.

Thus, cornstarch is the correct answer.