Question

The compound present in baking powder is:
(A) Sodium bicarbonate
(B) Sodium carbonate
(C) Potassium carbonate
(D) Potassium bicarbonate

Answer 1

Hint: Baking powder is a mixture of a carbonate or a bicarbonate with a weak acid. Baking powder is known as a dry leavening agent which contains baking soda, cream of tartar and sometimes cornstarch as a buffer. The addition of a buffer also serves the purpose of preventing acids and bases from prematurely reacting during the storage of baking powder.

Complete step by step answer:
We know that baking powder is used to increase the volume and to lighten the texture of the baked goods, so far fulfilling this condition, it is necessary to release carbon dioxide gas into the batter or dough. This release of carbon dioxide gas is possible, during the reaction of acid and a base, as a byproduct.
As from the above discussion, we have understood that baking powder consists of an acid and a base along with a buffer, which helps to control and prevent the reaction between this acid and base before the reaction is actually required. Thus, this acid and base can serve the purpose of giving out the carbon dioxide gas by reacting with each other.
Therefore, in aqueous state, that is when the baking powder is added to the batter, the reaction between the acid and the base takes place and releases carbon dioxide gas which helps to increase the volume of the dough and makes fluffy baked goods.
Now, it is to be noted that only sodium Bicarbonate \[NaHC{O_3}\] can be used for serving this purpose. This can be understood by the reaction given below:
\[NaHC{O_3}\left( {{\text{Sodium Bicarbonate - base}}} \right) + {H^ + }\left( {{\text{acid}}} \right) \to N{a^ + }\left( {{\text{salt}}} \right) + C{O_2} + {H_2}O\left( {{\text{water}}} \right)\]
Moreover, sodium carbonate and potassium carbonate cannot be used for this purpose because they are more alkaline and remain as such even after the reaction with the acid and this is not safe as it can burn mouth, while potassium bicarbonate, being a weaker base that sodium carbonate does not completely uses up all the acid.
 Our required answer is A.

Note:
Sodium bicarbonate is commonly called baking soda or bicarbonate of soda. It is a salt formed by reaction of sodium cation and bicarbonate anion.
i.e. \[N{a^ + } + HCO_3^ - \to NaHC{O_3}\]