Multiple choice

Parul wants to test the presence of proteins in a given food sample. Which of the following chemicals is/are used to test proteins in food?

  1. Copper sulphate and sodium chloride

  2. Iodine

  3. Potassium iodide

  4. Copper sulphate and caustic soda

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

To test the presence of proteins in any substance, 2 drops of copper sulphate followed by 10 drops of caustic soda are added. If the colour of the solution does not change, it means proteins are absent. If the colour changes from white to violet, it confirms the presence of proteins. Milk, egg and pulses give a positive test for proteins. So, the chemicals used are caustic soda and copper sulphate.