Production and Identification of Ammonia Gas
Purpose:
Determine the presence of ammonia gas in compounds. Identify ammonia gas by its distinctive
odor and its ability to turn red litmus paper to blue. Convert the ammonium ion into ammonia
gas through its reaction with sodium hydroxide.
Materials:
Household ammonia [NH3], 5%
Red litmus paper
Ammonium chloride solution [NH4Cl], 1 M
Medium test tubes, 18 x 150
Ammonium carbonate solution [(NH4)2CO3], 0.1 M Hot plate
Sodium hydroxide solution [NaOH], 1 M
Test tube rack
Egg white
Micropipets
Garden fertilizer
Test tube holder
Calcium oxide (CaO)
Stirring rod
Microspatula
10 mL Graduated cylinder
600 mL Beaker
safety goggles (worn at all times during the lab)
Background:
Ammonia (NH3) is a gas that dissolves readily in water. Some of the gas escapes from an
ammonia solution; thus, you can smell it, and it can react with litmus. When litmus turns blue, it
shows the presence of a base. Ammonia is a base. Ammonium salts react with strong bases such
as sodium hydroxide to produce ammonia:
NH4Cl(aq) + NaOH(aq) → NH3(g) + H2O(l) + NaCl(aq)
Some ammonium salts such as ammonium carbonate, which is found in smelling salts,
decompose without added base:
(NH4)2CO3(s) → 2NH3(g) + CO2(g) + H2O(l)
Protein, like egg white, contains nitrogen compounds that form ammonia when treated with a
strong base. Heat is usually necessary.
Procedure:
Begin a boiling water bath before beginning the other steps of the experiment.
1. Test household ammonia.
A. Place 2 mL of household ammonia into a medium test tube.
B. Fan a breeze toward you over the mouth of the test tube to detect the odor. NEVER
place your nose or face directly over any odorous chemical!
C. Hold a moist piece of red litmus paper over the test tube. Record your results.
2. Test ammonium chloride.
A. Place two milliliters of the ammonium chloride solution into a clean test tube.
B. Perform the test in Procedures 1B and 1C. Warm the solution if necessary in the
boiling water bath. Do not let the solution boil. Is ammonia detected?
C. Try another test: Add about 1 mL (20 drops) of sodium hydroxide solution to the
test tube containing ammonium chloride. CAUTION: Sodium hydroxide is a strong
base. Perform the test in Procedures 1B and 1C; warm the solution if necessary.
Do you detect ammonia molecules?
3. Test other substances.
A. Test about 20 drops of ammonium carbonate solution, which is found in smelling
salts, by performing the test in Procedures 1B and 1C. Is ammonia present?
B. Test approximately 4 or 5 pieces of garden fertilizer (use a microspatula), by adding 1
mL of sodium hydroxide solution, then performing the test in Procedures 1B and 1C.
Warm if necessary. Is ammonia present?
C. Test egg white by the following reaction: Place 1 mL (20 drops) of sodium hydroxide
solution in a test tube. Add a small scoop of solid calcium oxide. Mix. Add 1 mL
(20 drops of egg white. Test for ammonia by performing the test in procedures 1B
and 1C. Warm if necessary. Is ammonia detected?