Question

my presence can be detected by using water copper sulphate and caustic soda with food​

Answer 1

Answer: Proteins

Presence of proteins in the food can be identified by using water, copper sulfate and caustic soda

Firstly, the solid food is crushed and an adequate amount of water is added to the food sample

Then an equal amount of caustic soda (NaOH) and a few drops of 1% copper sulfate solution (CuSO₄) is added to sample

The presence of protein in the food sample is indicated by Purple/color

This test for proteins is known as the Biuret test  also known as Piotrowski's test