Coal is a potential source for ammonia. Comment.

Explanation

Coal on destructive distillation gives a liquid called coal tar, which also contains ammonical liquor.
When the liquid is treated with milk of lime and steam is blown, ammonia gas is evolved.
Concentrated ammonia solution can be prepared by dissolving in steam directly. A fertiliser ammonium sulphate is obtained when ammonia is absorbed in `H_(2)SO_(3)`.