Question

A baker found that the cake prepared by him is hard and small in size. Which ingredient has he forgotten to add that would have made the cake fluffy?

Answer 1

Sodium hydrogen carbonate (or baking soda) is used in making baking powder (used in making cakes, bread, etc.). Where the fluffiness to the dough to various food items needed, the use of baking soda takes place.

Complete step by step answer:
Baking powder is a mixture of baking soda constituting sodium hydrogen carbonate and tartaric acid which is edible mild acid. Baking powder on mixing with water (used in dough for bread and cake), the reaction of sodium hydrogen carbonate with tartaric acid occurs and the evolution of carbon dioxide gas occurs.
The carbon dioxide gas produced gets trapped in the wet dough and bubbles out slowly making the cake (or bread) to ‘rise’ and become soft and spongy. If the addition of baking powder is not done in the dough of bread and cake preparation, then the dough formed will be small and hard. If the dough for cake and bread are prepared using only sodium hydrogen bicarbonate that is baking soda then the production of sodium carbonate on heating of the dough will lead to the bitter taste of the bread or cake. The advantage of using tartaric acid along with baking soda is to neutralize the effect of any carbonate formed. And the sodium tartrate salt formed by the action of neutralization has a sweet taste.

Note:
When the baking powder is in dry condition, its constituents, the sodium hydrogen carbonate and tartaric acid are inert towards each other and do not react with each other. They react only in the presence of water. Commonly there are the chances when we confuse between baking soda and baking powder. Baking soda has a chemical name: sodium hydrogen carbonate.