Ammonia cannot directly prepare sulfate. However, it can be converted to sulphate by the following route:

- Ammonia is subjected to Ostwald's process to produce nitric acid.

- The nitric acid is mixed with concentrated sulphuric acid in 1:2 molar ratio to form mixed acid (oleum)

- Metal sulphates are then prepared from the oleum by dissolving the appropriate metals /oxides in them.

-For example, copper sulphate can be prepared by adding copper oxide (CuO) in oleum.