Question

HCl is dried by passing through CaO.
A. True
B. False

Answer 1

Hint: The hydrochloric acid gas is acidic in nature. The molecule ${\text{CaO}}$ is also called the quick lime. Guess about the nature of quick lime and think about the possible reaction that can occur in between the given chemicals and select the correct choice of answer.

Complete step by step answer:
- First of all we will discuss the nature of the given chemical molecules in question and think about the possible reactivity that can occur between them. The molecule ${\text{HCl}}$ is hydrochloric gas which is passed through the ${\text{CaO}}$. As we all know, hydrochloric gas is an acidic natural gas.
-Now in the case of the molecule ${\text{CaO}}$ which is also called quicklime has a basic nature of reactivity.
-Now as the hydrochloric gas is acidic in nature and the quick lime is basic in nature we know that there will be reactivity in an acid and a base which will give a neutralization reaction forming a product as water and other salt components.
-If the ${\text{HCl}}$ gas which is to be dried by passing through ${\text{CaO}}$ will give an acid-base reaction and will yield undesirable products by the reaction.
-Therefore, the statement ${\text{HCl}}$ is dried by passing through ${\text{CaO}}$ is a false statement.
So, the correct answer is “Option A”.

Note:
The molecule ${\text{CaO}}$ that is calcium oxide is a basic drying agent and it is generally used for the purpose of dehydrating basic and neutral gases. The alcohols which have low-boiling, amines, and some ethers are also dried with the help of calcium oxide.