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WAEC Biology 2002 Question 31

Question 31

Food Substances and Enzymes

When a food substance gives a purple colour on the addition of sodium hydroxide and a drop of copper sulphate, then the food substance is likely to contain

  1. A.carbohydrates
  2. B.fat
  3. C.protein
  4. D.sugar.
Show the answer and explanation

Answer: C (protein)

Explanation

Sodium hydroxide plus copper sulphate is the Biuret test; a purple (violet) colour shows protein.