Question

Given below from (i) to (iv) are food items.

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

Answer 1

The correct option is B

i and iii

The correct option is B.

Explanation of the correct option:

Statement i:

1. Boiled and mashed potato contains a high amount of starch.
2. Thus, this starch reacts with iodine to give a blue-black colored solution.

Statement iii:

1. Bread had high starch content.
2. It thus reacts with iodine to give a blue-black colored solution.

Explanation of the incorrect options:

Statement ii:

1. Glucose is a sugar molecule.
2. It does not contain starch.

Statement iv:

1. Mustard oil contains mainly only fatty acids.
2. It does not contain starch.

Final answer: The food items that contain starch and give a blue-black color when tested with iodine are boiled/mashed potatoes and slices of bread.