Question

Which of the following is an acidic gas
A.Hydrogen sulphide
B.Carbon dioxide
C.Argon
D.Both A and B

Answer 1

Hint: We must know that acid gas is any gas or a gaseous mixture which on combining with water forms an acidic compound.Acid gas is a particular typology of natural gas or any other gas mixture containing significant quantities of hydrogen sulfide $(H_2S)$, carbon dioxide $(CO_2)$, or similar acidic gases.

Complete step by step answer:
So let's start the discussion by asking what is an acid gas? Well, acid gas is any gas or a gaseous mixture which on combining with water forms an acidic compound or we can say that acid gas is any gas or gaseous mixture which have hydrogen sulphide or carbon dioxide with other acidic gases as a large part of their composition.
These gases are called acid gases for a reason they are known to cause toxic effects not just to the environment but also to human life. Hydrogen sulphide is known to cause a restriction to the piping of sour gases thanks to the phenomenon of sulphide stress cracking, as metals are quite sensitive to this gas.
While carbon dioxide is known to cause dizziness, headache, visual dysfunction, and much more when inhaled for a longer period. These gases are often confused with sour gases, but they are very different from each other as in the case of acidic gases they consist of a mixture of acidic gases like hydrogen sulphide and carbon dioxide. While sour gases just contain a specific amount of hydrogen sulphide gas in it.
To safeguard the environment against these harmful gases the amine gas treating process is used.

Hence by going with the above-explained definition the correct answer is option d) both a and b.

Note:
Also we have to know that acid gases are harmful for humans as they may cause dizziness, headache, visual and hearing dysfunction, rashes and other skin infections and many more. They are by-products of many reactions and processes and are kept in check to avoid any harmful effect on the person who is working near them.