Test For Carbohydrates, Fats & Proteins
(a) Test for carbohydrates : 
Take few drops of  iodine solution & add it into boiled rice or potato. The formation of blue-black colour confirms the presence of starch (carbohydrate).

(b) Test for fats : 
When  ghee / butter rubbed on white paper, that  portion of paper turns translucent indicating the presence of fats.

(c) Test for proteins : 
Take the few drops of egg albumin in a test tube and add a few drops of concentrated nitric acid to it. 
•    The white colour of the albumin changes to yellow. Now, pour the acid out of the test tube but keep the white of the egg in the test tube. 
•    Add a few drops of ammonium hydroxide to it.
•    The colour changes to violet which shows the presence of proteins.