Question

Ammonia gas can be dried by

• A. cone $H_2SO_4$
• B. $P_2O_5$
• C. $CaCl_2$
• D. quicklime

Answer 1

Answer: (D)

quicklime

Answer 2

Quicklime (CaO) is used for drying $NH_3$ gas because both
are basic, do not react. On the other hand, $H_2SO_4\, and\, P_2O_5$
are acidic, reacts with ammonia forming salts. $CaCl_2$ forms
complex with ammonia.