Testing for Ammonia Flashcards

All 5 cards in this deck

What is the chemical test for ammonia gas, and the result?

Hold damp red litmus paper in the gas — it turns blue.

What are the steps to test a solid for ammonium ions, $\mathrm{NH_4^+}$?
e.g. testing solid ammonium chloride

1. Add sodium hydroxide solution to the solid.
2. Warm the mixture gently.
3. Hold damp red litmus paper at the mouth of the tube — it turns blue, showing ammonia, so $\mathrm{NH_4^+}$ is present.

True or false? Ammonium ions give a white precipitate when sodium hydroxide solution is added.

False.
No precipitate forms; ammonia gas is released on warming.

Why must the litmus paper be damp in the test for ammonia gas?

The gas must dissolve in the water to show its alkaline effect on the litmus.

Why is the mixture warmed when testing for ammonium ions with sodium hydroxide solution?

To release the ammonia gas so it can be detected.