During the preparation of hydrogen chloride gas on a humid day, the gas is usually passed through the guard tube containing anhydrous calcium
chloride. The role of anhydrous 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
(c). Anhydrous CaCl2 absorbs moisture to keep the gas in dry state. Otherwise, it will dissolve in moisture to form hydrochloric acid.