Why is H2S not dried by Quicklime or Anhydrous Calcium Chloride?

Answer: Anhydrous Calcium Chloride (CaCl2) or Quicklime/Calcium oxide (CaO) is not used to dry H2S.

Because anhydrous CaCl2 reacts with acidic H2S to form calcium sulfide.

CaCl2 + H2S = CaS + 2HCl

H2S reacts with quicklime (CaO) to form calcium sulphide. Therefore, H2S gas cannot be dried by slaked lime.