Question

Given below are some food items.

(i) Potato. (ii) Mustard Oil.
(iii) A slice of bread (iv) Glucose solution

Which of the above will give blue –black colour when tested with iodine.

Answer 1

Starch gives blue black colour when tested with iodine. Among the given options, boiled & mashed potato and bread slice will have starch in them therefore, they will give blue black colour with iodine. While mustard oil and glucose solution doesn't not have starch content in them.

Answer 2

Answer:

Boiled and mashed and a slice of bread will give blue-black color when tested with iodine Amylose in starch is responsible for the formation of deep blue color in the presence of iodine.