(a) Name two constituents of baking powder.
(b) How does baking powder differ from baking soda?
(c) Explain the action of baking powder in the making of cake (or bread). Write equation of the reaction involved.
(a) Two constituents of baking powder are baking soda (sodium hydrogencarbonate) and tartaric acid.
(b) Baking powder is a mixture of baking soda (sodium hydrogencarbonate, NaHCO3) and a solid edible acid such as tartaric acid, whereas baking soda is a single compound (sodium hydrogencarbonate, NaHCO3).
(c) On mixing baking powder with water, which is present in the dough prepared for baking a cake or bread, sodium hydrogencarbonate reacts with tartaric acid to evolve carbon dioxide gas. The carbon dioxide gas gets trapped in the wet dough and bubbles out slowly, and the cake becomes soft and spongy.
Note: Here, H+ is from tartaric acid and Na+ is from sodium tartrate salt.
Lakhmir Chemistry 2013