Question

What is backing powder? How does it make the cake soft and spongy?

SCERT Telangana Class 10 General Science Ch Acid Bases and Salts

Answer 1

Baking powder is sodium bicarbonate.
It contains the basic bicarbonate and acidic compounds such as monocalcium phosphate and sodium aluminium phosphate. When mixed in a dough of floor the acidic component reacts with the basic component that causes the formation of carbon(II)oxide gas.
The carbon(II) oxide gas bubbles are trapped in the dough making it expand and get soft (or spongy).