Correct Answer - Option 1 : Calcium chloride
Explanation:
If we see how hydrogen chloride gas is prepared, we will see that the gas is usually passed through a guard tube (also known as a drying tube) containing anhydrous calcium chloride. The reason behind why anhydrous calcium chloride is used in guard tubes is because it is considered as a very good drying agent.
A drying tube or guard tube is a tube-like piece of apparatus used to house a disposable solid desiccant, wherein at one end the tube-like structure terminates in a ground glass joint for use in connecting the drying tube to a reaction vessel, for the purpose of keeping the vessel free of moisture
