Chemistry 2 Marks Questions

Due to the physical changes like change in temperature, pressure, or chemical change like change in pH, hydrogen bonds are disturbed. Because of this protein globules unfold and helix gets uncoiled and protein loses its biological activity. This is called denaturation of protein. Denaturation of protein is an irreversible process.
Example : The coagulation of egg white on boiling.

(i) Glucose does not react with iodine solution whereas starch gives blue colour with iodine solution.
(ii) Glucose does not undergo hydrolysis whereas hydrolysis of starch gives glucose.
(iii) Glucose gives red precipitate with Fehling's solution but starch does not give this test.

Aldose whose configuration of carbon atom C 2 differs are called epimers of each other and the process of conversion of one epimer into another epimer is called epimerization. Example: Glucose and mannose. In glucose the - OH group on C 2 is on the right hand side while in mannose it is on the left side.

Carbohydrates are classified as follows:

Reducing sugars have reducing properties, hence they reduce Fehling's solution and Tollens' reagent, like- all monosaccharides, maltose and lactose. Non-reducing sugars do not have reducing properties, hence they do not reduce Fehling's solution and Tollens' reagent. Example : Sucrose.