Question

A substance X which is used as an antacid reacts with dilute ${\text{HCl}}$ to produce a gas Y which is used in one type of fire extinguisher. Name the substance X and gas Y. Write a balanced equation for the chemical reaction which takes place.

Answer 1

Hint:The substance X is given to be an antacid which gives a gas Y on neutralization. Hence X should be a mild base and Y will be a gas that can extinguish a fire.

Complete step by step answer:
There are five general types of fire extinguishers on the basis of the substance used to put out the fire. They are water, foam, dry powder, wet chemicals and ${\text{C}}{{\text{O}}_2}$ gas.
Since the gas produced in the reaction is used in a type of fire extinguisher, the gas Y must be carbon dioxide, ${\text{C}}{{\text{O}}_2}$.
Since, carbon dioxide is produced when X reacts with hydrochloric acid, we can say that X must be either sodium carbonate or sodium bicarbonate. But sodium carbonate is a caustic base, which means it is able to burn, damage or destroy organic tissue slowly by chemical action. Thus, it is not edible and cannot be used as an antacid.
X is sodium bicarbonate (baking soda) and Y is carbon dioxide gas.
The balanced chemical equation for the reaction is given as,
${\text{NaHC}}{{\text{O}}_3} + {\text{HCl}} \to {\text{NaCl}} + {\text{C}}{{\text{O}}_2} + {{\text{H}}_{\text{2}}}{\text{O}}$

Additional information:
 In order to put out a fire we must use a substance that cannot be oxidized further or in other words, the substance should be completely oxidized, like carbon dioxide in which carbon cannot be further oxidized and can thus be used to put out the fire.

Note:
Sodium Bicarbonate is a salt of carbonic acid and sodium hydroxide. It is mildly basic and on neutralization yields carbon dioxide gas and is thus widely used in baking, fire extinguishers, as disinfectant, as antacids etc.