What is one method of qualitatively analyzing a given salt for presence of ammonia?

Using a reagent to obtain dirty brown precipitate

Typically, Nessler’s reagent is used to test for ammonia. Nessler’s reagent is an alkaline solution of potassium tetraiodomercurate (II). When it combines with ammonia it gives dirty brown precipitate due to the formation of [OHg₂.NH₂]I. Another method is to add a strong base and heat the mixture. The gas given off is pungent and turns red litmus blue.