Match List I with List II and select the correct answer using the code given below: List I | List II A. Starch Test | 1. Violet colour B. Protein Test | 2. Wet hands/moisture C. Fat Test | 3. Blue-black colour D. Water presence | 4. Oily patch

Correct Option The correct option is A-3, B-1, C-4, D-2 Explanation Food components such as carbohydrates, proteins, and fats are macromolecules that can be identified using specific qualitative tests. These tests rely on chemical reactions that produce distinct color changes or physical indicators to confirm the presence of specific nutrients. Detailed Analysis - A. Starch Test - 3. Blue-black colour: The standard test for starch involves the use of a dilute iodine solution. When iodine interacts with the helical structure of starch (amylose), it forms a complex that results in a characteristic blue-black colour. - B. Protein Test - 1. Violet colour: The presence of proteins is detected using the Biuret test, which involves adding copper sulphate and caustic soda (sodium hydroxide) to the food solution. The copper ions react with peptide bonds in an alkaline environment to produce a violet colour. - C. Fat Test - 4. Oily patch: Lipids (fats) are tested by crushing a small quantity of the food item on a piece of paper. If the paper develops an oily patch that becomes translucent (allowing partial light to pass through), it confirms the presence of fats. - D. Water presence - 2. Wet hands/moisture: Many raw food ingredients contain significant amounts of water. Crushing or handling fresh vegetables or fruits often releases moisture, resulting in wet hands or dampness on the testing surface. Key Takeaway Diagnostic Indicators for Biomolecules: - Starch: Iodine Solution → Blue-black colour. - Protein: Copper Sulphate + Caustic Soda → Violet colour. - Fat: Paper Test → Translucent oily patch.

NCERT Class 6 Science — Chapter 2: Components of food

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Match List I with List II and select the correct answer using the code given below:

List I	List II
A. Starch Test	1. Violet colour
B. Protein Test	2. Wet hands/moisture
C. Fat Test	3. Blue-black colour
D. Water presence	4. Oily patch

Official previous-year question

Verified 1 Aug 2026.

Options

AA-3, B-4, C-1, D-2
BA-1, B-2, C-3, D-4
CA-1, B-3, C-2, D-4
DA-3, B-1, C-4, D-2

Did you get this right?

Solution

Correct Option

The correct option is

A-3, B-1, C-4, D-2

Explanation

Food components such as carbohydrates, proteins, and fats are macromolecules that can be identified using specific qualitative tests. These tests rely on chemical reactions that produce distinct color changes or physical indicators to confirm the presence of specific nutrients.

Detailed Analysis

A. Starch Test - 3. Blue-black colour: The standard test for starch involves the use of a dilute iodine solution. When iodine interacts with the helical structure of starch (amylose), it forms a complex that results in a characteristic blue-black colour.
B. Protein Test - 1. Violet colour: The presence of proteins is detected using the Biuret test, which involves adding copper sulphate and caustic soda (sodium hydroxide) to the food solution. The copper ions react with peptide bonds in an alkaline environment to produce a violet colour.
C. Fat Test - 4. Oily patch: Lipids (fats) are tested by crushing a small quantity of the food item on a piece of paper. If the paper develops an oily patch that becomes translucent (allowing partial light to pass through), it confirms the presence of fats.
D. Water presence - 2. Wet hands/moisture: Many raw food ingredients contain significant amounts of water. Crushing or handling fresh vegetables or fruits often releases moisture, resulting in wet hands or dampness on the testing surface.

Key Takeaway

Diagnostic Indicators for Biomolecules:

Starch: Iodine Solution → Blue-black colour.
Protein: Copper Sulphate + Caustic Soda → Violet colour.
Fat: Paper Test → Translucent oily patch.

Your note

More from Chapter 2: Components of food

Consider the following statements regarding the testing of nutrients in food items: 1. A blue-black colour produced after adding dilute iodine solution indicates the presence of starch. 2. A violet colour produced after adding copper sulphate and caustic soda indicates the presence of fats. Which of the statements given above is/are correct?

easy

Consider the following statements regarding the preparation of solutions for nutrient testing: 1. A dilute solution of iodine is prepared by dissolving copper sulphate in water. 2. Copper sulphate solution is prepared by dissolving copper sulphate in water. 3. Caustic soda solution is prepared by dissolving caustic soda in water. Which of the statements given above are correct?

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With reference to the test for fats in food items, consider the following statements: 1. An oily patch on paper generally indicates the presence of fat in the food item. 2. If a food item contains water, it will never leave a wet patch on the paper. 3. The paper should be heated strongly to check for the presence of starch. Which of the statements given above is/are correct?

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Consider the following statements about dietary fibres: 1. Dietary fibres are also known as roughage. 2. They are mainly provided by animal products like milk and eggs. 3. They do not provide any nutrient to our body. Which of the statements given above are correct?

medium

With reference to the role of water in the body, consider the following statements: 1. Water prevents the body from absorbing nutrients from food. 2. It helps in throwing out some wastes from the body as urine and sweat. 3. The body gets water from liquids drunk as well as from cooked food items. Which of the statements given above are correct?

easy

Keep practising Chapter 2: Components of food

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Correct Option

The correct option is

A-3, B-1, C-4, D-2

Explanation

Detailed Analysis

A. Starch Test - 3. Blue-black colour: The standard test for starch involves the use of a dilute iodine solution. When iodine interacts with the helical structure of starch (amylose), it forms a complex that results in a characteristic blue-black colour.
B. Protein Test - 1. Violet colour: The presence of proteins is detected using the Biuret test, which involves adding copper sulphate and caustic soda (sodium hydroxide) to the food solution. The copper ions react with peptide bonds in an alkaline environment to produce a violet colour.
C. Fat Test - 4. Oily patch: Lipids (fats) are tested by crushing a small quantity of the food item on a piece of paper. If the paper develops an oily patch that becomes translucent (allowing partial light to pass through), it confirms the presence of fats.
D. Water presence - 2. Wet hands/moisture: Many raw food ingredients contain significant amounts of water. Crushing or handling fresh vegetables or fruits often releases moisture, resulting in wet hands or dampness on the testing surface.

Key Takeaway

Diagnostic Indicators for Biomolecules:

Starch: Iodine Solution → Blue-black colour.
Protein: Copper Sulphate + Caustic Soda → Violet colour.
Fat: Paper Test → Translucent oily patch.