Ammonia (Oxford AQA IGCSE Chemistry)

Test for Ammonia

• Ammonia is a gas with a characteristic sharp choking smell that turns damp red litmus paper blue

• Hold the litmus paper near the mouth of the test tube, but be careful to avoid touching the sides of the test tube

• If you are testing for ammonia produced from ammonium ions and sodium hydroxide, avoiding touching the sides to prevent traces of sodium hydroxide from also turning the red litmus paper blue

Test for ammonia gas

• Another test for ammonia is to react the gas with hydrogen chloride gas from concentrated hydrochloric acid 

• A white smoke of ammonium chloride is formed if ammonia gas is present:

NH₃ + HCl → NH₄Cl