Baking soda

The chemical formula of baking soda is NaHCO₃. The chemical name of baking soda is sodium hydrogen carbonate or sodium bicarbonate.

Manufacture of baking soda

The baking soda can be manufactured on commercial scale by Solvay’s process. The manufacture of sodium carbonate by Solvay process includes many steps which are discussed below:

1. Saturation of sodium chloride with ammonia

First of all a cold and concentrated solution of sodium chloride called brine is saturated with ammonia to get a solution called ammoniacal brine.

2. Carbonation

In the second step the ammoniacal brine prepared in first step is dropped from the top of a tower called carbonating tower and carbon dioxide gas is passed into the tower from near its base. The carbonating tower has partitions which are made up of iron plates with hole in the center and covered with perforated plate. The function of these partitions is to slow down the down coming ammoniacal brine solution so that the upcoming carbon dioxide has enough time to react with it completely.

So as the ammoniacal brine comes down from the top of the carbonating tower, it reacts with carbon dioxide to form precipitates of baking soda or sodium hydrogen carbonate:

Properties of Baking Soda

1. Baking soda is a white crystalline powder which is sparingly soluble in water.
2. The aqueous solution of baking soda is mildly alkaline in nature.
3. Action of heat:- On heating, sodium bicarbonate decomposes to form sodium carbonate as given below:

Uses of Baking Soda

1. Baking soda is used for preparing baking powder which is used extensively in the preparation of bread, cakes and other confectionary items.

   Actually baking powder is mixture of baking soda and tartaric acid. When baking powder is mixed in dough for preparing cakes or bread and heated then baking soda decomposes into sodium carbonate and carbon dioxide gas. This carbon dioxide gas tries to come out of the cake due to which the cake rises and becomes light and fluffy. Now the presence of sodium carbonate in cake makes it bitter so to remove its bitterness the tartaric acid reacts with it. If incidentally a baker forgets to add baking powder in the dough during preparation of cakes or bread then it will not rise and will become hard and small in size.

2. Baking soda is also used as an antacid in medicines to remove acidity of stomach because it is alkaline in nature so it has the tendency of neutralizing acids present in the stomach.
3. Baking soda is used in fire extinguishers.

Test your understanding and answer these questions:

1. What is chemical name and formula of baking soda.
2. How baking soda is manufactured?
3. Give uses of baking soda.