Question

Name the drying agent used for purifying hydrogen chloride gas.

Answer 1

Hint :Drying agents are also called desiccants. They exist in various forms and can be used in foods, pharmaceuticals, packing, manufacturing industries and electronics. A drying agent should have hygroscopic properties that induce or sustain dryness in its vicinity. Examples of drying agents are calcium chloride, conc. Sulphuric acid, etc.

Complete Step By Step Answer:
We can define drying agents as the hygroscopic substances which protects any substance from being reacted with moisture and it itself absorbs moisture or induces dryness in its vicinity. They are also known as desiccants.
Now, if we name the compound used as a drying agent for purifying hydrogen chloride gas then, that is Concentrated Sulphuric Acid $ (Conc.{H_2}S{O_4}) $ . Concentrated Sulphuric Acid is a very good drying agent and can be used as Dehydrating agent too because it has a very strong affinity towards water and hence, it absorbs water quickly. On absorbing water or moisture from the air surrounding it, it gets diluted in nature and hence shows dehydrating properties. Concentrated sulphuric acid has a hygroscopic property and induces dryness in its vicinity. Hence, concentrated sulphuric acid is the drying agent used for purifying hydrogen chloride gas.

Note :
Sulphuric acid has many applications in many reactions and industries other than dehydrating or drying agents such as in many concentrations the acid can be used for the manufacture of fertilizers, dyes, drugs, explosives, pigments, detergents, and inorganic salts. It is also used in petroleum refining and various metallurgical processes.