Name the substance used for drying ammonia
Quicklime or calcium oxide CaO is used as a drying agent during the production of ammonia.
A drying agent is a substance which is capable of removing moisture from a substance. Calcium chloride and phosphorous pentoxide are not drying agents because they don't absorb water.
Quicklime absorbs thick water produced in the reaction in the form of water vapour. One thing you should remember is that the drying agent cannot be used in a reaction if it tends to react with the products of the reaction. Since Quicklime CaO and ammonia (NH3) are basic compounds thus they cannot react with each other. But, concentrated sulphuric acid reacts with ammonia hence, it is not advisable.
That's why quicklime (CaO) is used for drying ammonia.