Baking soda and baking powder are amongst the most common kitchen ingredients. These are primarily used as leavening agents or raising agents in doughs and batters. Their names are quite similar, but they are not the same. In this article, we will discuss both and also the key differences between them.
Baking soda is a sodium salt with the chemical name Sodium Bicarbonate. The chemical formula of baking soda is NaHCO3. As the formula suggests, it comprises of Na+ and HCO3- ions.
Figure 1 : Sodium Bicarbonate or Baking Soda
As shared earlier, baking soda is primarily used as a leavening or raising agent in cooking. Baking soda acts as a leavening agent because it is capable of releasing carbon dioxide gas in the dough or batter. There are two ways in which baking soda can release this gas.
Baking soda reacts with acids to form carbon dioxide gas. The chemical reaction which takes place is as follows:
NaHCO3 + H+ → Na+ + CO2 + H2O
Many edible items can be used as acids (or providers of H+ ion) for this reaction to happen. Some of the common items are vinegar (acetic acid), curd (lactic acid) and citrus juice (citric acid).
Sodium bicarbonate decomposes into sodium carbonate, water and carbon dioxide gas upon heating. This thermal decomposition happens at temperatures above 80oC.
2 NaHCO3 → Na2CO3 + H2O + CO2
This is not a preferred method to use baking soda as a leavening agent because sodium carbonate thus formed can alter the taste of the end product.
Baking soda is both mined and produced in factories. It is known as nahcolite in its mineral form. In factories, it is produced by reacting carbon dioxide and water with sodium carbonate.
Na2CO3 + CO2 + H2O → 2 NaHCO3
Baking powder, like baking soda, is also used as a leavening agent. As we discussed in the previous section, leavening agents give the rising of dough or batter because they help in releasing carbon dioxide gas in the mixture. And to do that, we need a base and an acid in the mixture. In case of baking soda, the acid was supplied from outside while sodium bicarbonate acted as a base. On the other hand, both acid and base are supplied together in baking powder. So, baking powder can be considered much easier to use than baking soda. Typically, baking powder consists of a mixture of a base, an acid and a buffer or stabler.
As with baking soda, sodium bicarbonate can be used as a base in baking powder as well. Cream of tartar is typically used as the acidic component, and cornstarch is typically used as the stabilizer. Sometimes, two acidic components are used instead of one. Such baking powders are also called double-acting baking powders.
The chemical reaction of baking powder is similar in nature to that of baking soda. Here also, H+ ion is used and Na+ ion is released by sodium bicarbonate, as per the following reaction (assuming cream of tartar is used as the acidic component):
NaHCO3 + KHC4H4O6 ----> KNaC4H4O6 + H2O + CO2
If a second acidic component is also added in baking powder, say sodium aluminium sulphate, then the baking powder also gives a second rise to the dough or batter when heated. The reaction at high temperature is as follows :
NaAl(SO4)2 + 3 NaHCO3 ----> Al(OH)3 + 2 Na2SO4 + 3 CO2
This ends our coverage on Baking soda and Baking powder. We hope you enjoyed learning and were able to grasp the concepts. We hope after reading this article you will be able to answer questions related to this topic. If you are looking for solutions of NCERT Textbook problems based on this topic, then log on to Vedantu website or download Vedantu Learning App. By doing so, you will be able to access free PDFs of NCERT Solutions as well as Revision notes, Mock Tests and much more.