Question

State the chemical property in each case on which the following uses of baking soda are based upon:
(i) As an antacid
(ii) As a constituent in making baking powder
(iii) In soda-acid fire extinguishers

Hint:

Baking soda works as an antacid, leavening agent, and in fire extinguishers by reacting with acids to produce carbon dioxide, which neutralizes acidity or displaces oxygen.

Answer 1

(i) As an Antacid:
Baking soda (sodium bicarbonate, NaHCO₃) neutralizes excess acid in the stomach. When it reacts with hydrochloric acid (HCl), it forms sodium chloride (NaCl), water, and carbon dioxide, which relieves acidity: \[ \text{NaHCO}_3 (aq) + \text{HCl} (aq) \rightarrow \text{NaCl} (aq) + \text{H}_2\text{O} (l) + \text{CO}_2 (g) \]
(ii) As a Constituent in Making Baking Powder:
Baking soda is a key ingredient in baking powder. When baking soda reacts with an acid (such as tartaric acid or citric acid), it produces carbon dioxide gas. This gas helps dough rise by creating bubbles: \[ \text{NaHCO}_3 (aq) + \text{H}_2\text{O} (l) \rightarrow \text{NaOH} (aq) + \text{CO}_2 (g) \]
(iii) In Soda-Acid Fire Extinguishers:
In soda-acid fire extinguishers, baking soda reacts with sulfuric acid to produce carbon dioxide gas, which helps in extinguishing the fire by displacing oxygen: \[ \text{NaHCO}_3 (s) + \text{H}_2\text{SO}_4 (aq) \rightarrow \text{Na}_2\text{SO}_4 (aq) + \text{CO}_2 (g) + \text{H}_2\text{O} (l) \]