Question

Which of the following compounds are used to test the presence of proteins?

• A. Copper sulphate
• B. Sodium hydroxide
• C. Potassium chloride
• D. Iodine solution

Answer 1

Answer: (A), (B)

The correct options are
A Copper sulphate
B Sodium hydroxide

$\bullet$ Copper sulphate and sodium hydroxide solution are used to test the presence of protein in food.
$\bullet$ Food sample to be tested is converted into a powder or paste form. To this water is added.
$\bullet$ Take 10 drops of this solution into a test tube. Add 2 drops of 2% copper sulphate solution and 10 drops of 10% sodium hydroxide solution and mix well.
$\bullet$ Formation of purple or violet colour confirms the presence of protein in the sample.