Question

In an experiment, Radha took small amounts of an unknown food item in a test tube. Then, she added two drops of copper sulphate CuSO₄ solution in the test tube along with a few drops of caustic soda solution. After a few minutes, the colour of the food item changed to violet.In the given experiment, the change in colour of the food item to violet indicates the presence of

Answer 1

The change in colour of the food item to violet indicates :

• The change in color of the food item to violet after the addition of Copper sulfate and Caustic soda solution indicates the presence of proteins in the food item.
• This test is a burette test that helps to determine the presence of proteins.
• During the test ${\mathrm{Cu}}^{2+}$ ions are reduced to ${\mathrm{Cu}}^{+}$ in presence of alkali, which in turn binds with proteins to yield a violet colour.

Hence, the change in color of the food item to violet indicates the presence of proteins in the food item.