Multiple choice

Which chemical(s) is/are used to test protein in food?

  1. Copper sulphate and sodium chloride

  2. Iodine

  3. Caustic soda only

  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, two drops of copper sulphate followed by ten 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 positive test for proteins. So, the chemicals used are caustic soda and copper sulphate.

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