Question

Q54) Consider the following statements

i) Iodine solution is used to test the presence of fat.

ii) Vitamins have no nutritive value, but provide protection against disease.

iii) Mixture of copper sulphate and caustic soda is used to test the presence of proteins.

Which of the above statements are true?

• A. a) iii only
• B. b) i and ii only
• C. c) ii and iii only
• D. d) none of these

Answer 1

The correct option is A

a) iii only

A)

Explanation:

Test for Carbohydrates:

1. Take small quantity of the food item to be tested on a porcelain tile.
2. Dilute it with two drops of water.
3. Put 2-3 drops of iodine solution on it.
4. Observe the colour of the food item.
5. Change of colour in the food item into blue-black indicates the presence of starch in the food item.

Test for Proteins:

1. Take a small quantity of the food item to be tested.
2. Grind the food item and powder it by mashing.
3. Put the food item into a test tube.
4. Add 10 drops of water into the same test tube.
5. Add two drops of copper sulphate solution to the same test tube.
6. Add 10 drops of caustic soda solution and shake the same test tube.
7. Observe the colour of the mixture.
8. Violet colour indicates the presence of proteins in the tested food item.

Test for Fats:

1. Take a small quantity of the food item to be tested.
2. Wrap the food item in a small piece of paper.
3. Crush the food item wrapped in the paper.
4. Straighten the paper.
5. Dry the paper by keeping it in sunlight for a while.
6. Observe the paper.
7. An oily patch on the paper indicates the presence of fat in the tested food item.

Vitamins are required in trace amounts, and play a major role in protection against diseases. They have lesser nutritive value, but we cannot say that they don’t have any nutritional value.