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) Antacid Use:
Sodium bicarbonate (baking soda, NaHCO₃) reduces stomach acid. It neutralizes hydrochloric acid (HCl), producing sodium chloride (NaCl), water, and carbon dioxide, alleviating acidity: \[\text{NaHCO}_3 (aq) + \text{HCl} (aq) \rightarrow \text{NaCl} (aq) + \text{H}_2\text{O} (l) + \text{CO}_2 (g)\]
(ii) Baking Powder Component:
Baking soda is a key baking powder ingredient. It reacts with an acid (like tartaric or citric acid), generating carbon dioxide gas. This gas causes dough to rise by forming bubbles: \[\text{NaHCO}_3 (aq) + \text{H}_2\text{O} (l) \rightarrow \text{NaOH} (aq) + \text{CO}_2 (g)\]
(iii) Soda-Acid Fire Extinguishers:
In these extinguishers, baking soda reacts with sulfuric acid, creating carbon dioxide. This gas extinguishes fires by removing oxygen: \[\text{NaHCO}_3 (s) + \text{H}_2\text{SO}_4 (aq) \rightarrow \text{Na}_2\text{SO}_4 (aq) + \text{CO}_2 (g) + \text{H}_2\text{O} (l)\]