During the preparation of hydrogen chloride gas on a humid day, the gas is usually passed through the guard tube containing calcium chloride. The role of calcium chloride taken in the guard tube is to
(A) absorb the evolved gas
(B) moisten the gas
(C) absorb moisture from the gas
(D) absorb Cl– ions from the evolved gas
Answer
Since the day is humid, we need something to absorb the moisture.
Calcium chloride is a hygroscopic salt i.e. it absorbs moisture from the surroundings.
Therefore, the correct option is
(c) - absorb moisture from the gas
