Given below from (i) to (iv) are some food items.
(i) Boiled and mashed potato
(ii) Glucose solution
(iii) A slice of bread
(iv) Mustard oil
Which of the above will give blue-black colour when tested with iodine?
(a) (i) and (ii)
(b) (i) and (iii)
(c) (ii) and (iii)
(d) (iii) and (iv)

Correct Answer: (b) (i) and (iii)

Explanation:

Starch when reacted with iodine solution, gives a blue-black color.

Thus, starch present in boiled & mashed potatoes and bread slices when reacted with iodine gives a blue-black color.

From the above options, mustard oil and glucose solution do not contain starch.

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Updated on: 12-Jan-2023

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