Question

Concentrated nitric acid is used in a test to detect adulteration of :

• A. Cooking oil
• B. Milk
• C. Salt
• D. Tea powder

Answer 1

The correct option is A Cooking oil

I. Test for oil- To detect the presence of argemone oil in cooking oil or fat,take some quantity of oil in a test tube and equal quantity of concentrated nitric acid and shake carefully. Red to reddish brown colour in lower layer would indicate the presence of argemone oil.
II. Test for milk- To detect the presence of starch in milk,add a few drops of tincture of iodine or iodine solution. Formation of blue colour indicates the presence of starch.
III. Test for salt or tea powder- To detect the presence of some foreign particle in them,rub them between the palms and smell or dissolve them in water to detect saw dust or brick powder.