School Science Lessons
UNChem1b
2018-10-31
Please send comments to: J.Elfick@uq.edu.au

3.33 Ammonia
Table of contents
3.33.0 Ammonia
3.33.2 Ammonium compounds
3.33.01 Ammonia solution
3.33.1 Tests for ammonia

3.33.0 Ammonia, NH3
See: Ammonia Elements, Compounds, (Commercial)
Ammonia, NH3, and the ammonium ion, NH4+: 12.11.3
Ammonia (NH3), monodentate ligand
Ammonia gas, NH3
Ammonium compounds: 3.33.2
Ammonium ion (NH4+), solution, Tests for ammonia, ammonium ions: 12.11.3.11
Ammonium ion (NH4+), solution, Tests for ammonia, ammonium ions: Nessler's reagent
Ammonia (25-28%) Specific gravity (relative density 0.91)
Ammonia absorbs impurities on charcoal
Ammonia anhydrous, ammonia liquefied gas, ammonia gas
Ammonia, anhydrous hazards: 3.8.1
Ammonia cell test (0.2-10 mg / litre)
Ammonia cell test kit (1-28 mg / litre)
Cloudy ammonia
Prepare ammonia gas: 3.33.0
Prepare ammonia, Haber process: 3.33.01
3.33.0 Prepare ammonia gas
3.33.01 Prepare ammonia, Haber process
3.32.0 Prepare gases with a gas generation apparatus

Ammonia with copper oxide (redox reaction): 12.2.6.3
Ammonia with copper sulfate: 13.6.8
Ammonia with sulfuric acid, acid-base neutralization: 12.8.1
Ammonia with copper sulfate solution: 3.33.4
Ammonia with cobalt chloride solution: 3.33.5
"Ammonium hydroxide": 3.33.01
Catalytic oxidation of ammonia, with red-hot platinum wire: 13.6.6.1
Catalytic oxidation of ammonia, with chromium (III) oxide: 13.6.6.2
Catalytic oxidation of methyl alcohol, and ammonia solution: 17.3.12
Density of gases, Ammonia (Table)
Diffusion rates of ammonia and hydrogen chloride gases: 10.1.2
Group 6 Tests for K+, Mg2+, Na+, NH4+: 4.6
Hartshorn
Iron (II) sulfate with ammonia: 12.1.2
Liquid ammonia, anhydrous ammonia fertilizer: 6.17.3
Magnesium sulfate with ammonia: 12.1.10
Prepare chrome alum: 12.14.4
Prepare insoluble hydroxides with ammonia solution: 3.33.2.1
Prepare iron (III) ammonium alum: 12.14.3
Prepare rayon, copper (II) sulfate with ammonia solution: 3.4.8.0
Prepare rayon, basic copper carbonate with ammonia solution: 3.4.8.1
QAC (quaternary ammonium compounds), swimming pools: 18.7.56
Reactions of ammonium salts and potassium salts with water: 14.2.1
Reduce copper (II) oxide to copper with ammonia: 13.6.7
Reduce nitrates to ammonia: 12.11.2.2
Storing alkalis, ammonia solution: 3.4.13.2
Tests for hydroxyl ions (hydroxide ions), ammonia solution: 13.6.5
Tests for hydrogen chloride with ammonia solution: 3.42.1.6
Tests for ammonia: 3.33.1
Uses of ammonia: 3.33.3
Weak electrolytes, ammonia solution: 15.8.4

3.33.01 Ammonia solution, [NOT "ammonium hydroxide, NH4OH".]
Ammonia solution is shown as NH3 (aq) because "NH4+" ions and "OH-" ions can be detected, but not "NH4OH".
Ammonia solution, aqueous ammonia, spirits of hartshorn, Toxic by all routes, Lung & eye irritant
Ammonia solution (10% ammonia solution): 5.3.4
Ammonia solution < 2 M, ammonium hydroxide, < 5%, Not hazardous, > 18 M, 35-50%, > 50%, 2-5 M, 5-10%
Ammonia solution 3 M: dilute 200 mL (28%) 14.8 M concentrated solution to 1 litre of water
Ammonia solution 4 M: dilute 220 mL (28%) 18 M concentrated solution to 1 litre of water ("ammonium hydroxide")
Ammonia solution 5-18 M, 10-35%, ammonium hydroxide, cloudy ammonia
Ammonia solution, concentrated, solution 35% w / w, SG 880, 880 ammonia, concentrated, liquor ammonia fort
Ammonia solution, For 2 M solution, dilute 330 mL of 10% soln in 1 L water
Ammonia solution in a neutralization reaction: 3.33.3
Ammonia solution test for hydrogen chloride: 3.42.1.6
Ammonia solution: Ammonium hydroxide (>25% in water), solution of ammonia in water, ammonia hydrate
Ammonia solution: Ammonium hydroxide, prepare by mixing household ammonia cleaner with water.

3.33.1 Tests for ammonia
Ammonia fountain test: 3.33.1.6
Litmus tests for ammonia: 3.33.1.3
Nessler's reagent test for ammonia: 3.33.1.7
Odour test for ammonia: 3.33.1.2
Sodium bicarbonate test for ammonia: 3.33.1.5
Solubility tests for ammonia: 3.33.1.4
Tests for ammonia, ammonium ions: 12.11.3.11
Tests for ammonia or amino acids or proteins with ninhydrin: 10.2.2.5a
Tests for ammonium compounds: 3.33.1.8

3.33.3 Uses of ammonia
Use ammonia solution, in the soapy wash water, to loosen dirt, add whiteness and prevent shine, remove burnt food in aluminium pans,
clean tops of stoves, remove fruit juice stains.

3.33.2 Ammonium compounds
Ammonium ion NH4+
Ammoniacal silver nitrate solution, Tollens' reagent
Ammonium acetate, CH3CO2NH4, ammonium ethanoate, used for buffers
Ammonium acetate, Low cost, drops of ammonia solution with white vinegar until red to litmus paper
Ammonium alum, aluminium ammonium sulfate (VI)-12-water, AlNH4(SO4)2.12H2O, Tschermigite mineral
Ammonium alum: Alums
Ammonium benzoate
Ammonium bicarbonate, ammonium hydrogen carbonate, NH4HCO3, white crystals, crystal ammonia, used in some baking powders.
Ammonium bromide, used in smelling salts
Ammonium carbonate
Ammonium chlorate
Ammonium chloride
Ammonium chromate, NH4)2CrO4, yellow monoclinic crystals, decomposes at 185oC, loses ammonia gas, alkaline solution, needs
cool storage.
Ammonium copper (II) chloride, tetramine copper (II) chloride
Ammonium dichromate
Ammonium dihydrogen phosphate, ammonia dihydrogen orthophosphate (V), ammonium biphosphate, Harmful if ingested
Ammonium dihydrogen phosphate, monobasic ammonium phosphate (piezoelectric crystal in microphones and transducers)
Ammonium ethanoate, CH3CO2NH4, ammonium acetate, ammonium oxalate
Ammonium ferric citrate (brown)
Ammonium ferric citrate (green)
Ammonium ferric citrate, ferric ammonium citrate (from citric acid), (food acid) (dietary iron supplement) (in breakfast cereals,
diet formulae), E381
Ammonium ferric sulfate, iron (III) ammonium sulfate
Ammonium ferrous (II) sulfate, iron (II) ammonium sulfate
Ammonium ferrous sulfate (COD determination)
Ammonium fluoride
Ammonium formate
Ammonium fumarate (food acid), E368
Ammonium heptamolybdate tetrahydrate
Ammonium hexafluorovanadate, ammonium hexafluoridovanadate (V) (NH4)3VF6
Ammonium hydrogen carbonate, NH4HCO3, ammonium bicarbonate, Smelling salts (ammonium carbonate): 12.16.3.5
Ammonium hydrogen carbonate, Baking powder: 19.1.6.1
Ammonium hydrogen difluoride
Ammonium hydrogen phosphate, diammonium hydrogen phosphate (NH4)2HPO4, in fertilizers, Toxic if ingested
Ammonium hydrogen sulfate
Ammonium iodide, Harmful if ingested
Ammonium iron (II) sulfate, Fe(NH4SO4), Mohr's salt
Ammonium iron (II, III) phosphate, NH4Fe2(PO4)2, containing Fe II and Fe III, is the first example of a mixed-valence ammonium
iron phosphate.
Ammonium magnesium chloride
Ammonium magnesium phosphate, struvite mineral ((NH4)MgPO4.6H2O), (used in phosphate recycling from sewage)
Ammonium malate (food acid), E349
Ammonium metavanadate, ammonium vanadate, NH4VO3
Ammonium molybdate
Ammonium nickel (II) sulfate 6H2O, Harmful if ingested
Ammonium nitrate
Ammonium nitrite, Toxic if ingested
Ammonium nitrite, Prepare nitrogen gas with ammonium nitrite: 3.46
Ammonium oxalate
Ammonium perchlorate, Toxic if ingested, Explosive, Not permitted in schools
Ammonium persulfate
Ammonium phosphate
Ammonium sodium hydrogen phosphate (V)-4-water, Na(NH4)HPO4.4H2O, ammonium sodium hydrogen orthophosphate,
microsmic salt (from urine)
Ammonium purpurate, C8H8N606, (Murexide)
Ammonium sodium hydrogen phosphate (V)-4-water, Na(NH4)HPO4.4H2O, ammonium sodium hydrogen orthophosphate,
microsmic salt (from urine)
Ammonium sulfate (NH4)2SO4
Ammonium sulfamate, H6N2O3S, herbicide for difficult weeds, Toxic
Ammonium sulfide solution (>20% in water) (10% solution) (20% solution), Highly toxic fumes
Ammonium tartrate (NH4)2C4H4O6 , Ammonium tartrate dibasic, "BioXtra", nitrogen source for biology experiments
Ammonium thiocyanate, NH4NCS, Highly toxic fumes, white yellow, monoclinic, deliquescent crystals, M P 16oC, test for ferric iron,
in fixatives and explosives.
Ammonium thiocyanate, Tests for iron: 12.11.3.20
Ammonium thiosulfate, diammonium thiosulfate (NH4)2S2O3, photography rapid fixer, fertilizer, reducing agent, Environment danger
Ammonium triiodide, nitrogen triiodide: 12.19.6.13
Ammonium vanadate, ammonium metavanadate, Harmful if ingested
"Cloudy ammonia", household ammonia, contains powdered soap in addition to ammonia.
Diammonium copper (II) sulfate (VI)-6-water, ammonium cupric sulfate
Diammonium hydrogen phosphate, ammonium phosphate dibasic
Ferrous ammonium sulfate, Mohr's salt: Ammonium iron (II) sulfate,
Monammonium phosphate
Reactions of ammonium salts and potassium salts with water: 14.2.1
Tri-ammonium citrate (food acid, acidity regulator) (Health risk, liver and pancreas problems), E380

Ammonium carbonate
Ammonium carbonate with acids: 12.12.3
Ammonium carbonate with alkalis: 12.12.2
Ammonium carbonate, For 2 M solution, 300 g in 450 mL 10% NH3, then dilute in 1 L water
Ammonium carbonate precipitates: 12.12.4
Ammonium carbonate, smelling salts: 12.16.3.5
Ammonium carbonate solution precipitates metal carbonates: 12.16.3.4
Ammonium carbonate with ethanoic acid: 14.2.3
Ammonium carbonate decomposition: 12.12.1
Heat ammonium carbonate (smelling salts): 12.16.3.1
Precipitates with ammonium carbonate: 12.12.4
Smelling salts: 12.16.3.5

Ammonium carbonate (NH4)2CO3 or (NH4)2CO3.3H2O, crystal ammonia, white crystalline solid, Harmful if inhaled
Harmful if swallowed or inhaled, irritates skin, eyes, respiratory tract
Ammonium carbonate (NH4)2CO3, sal volatile, aromatic spirits of ammonia, hartshorn salt, ammonium sesquicarbonate, bakers'
ammonia, crystal ammonia, colourless crystals or white powder, ammonia-like odour, very soluble, decomposes in hot water, E503,
Ammonium carbonate is double salt, ammonium hydrogen carbonate, (ammonium aminomethanoate, carbamate),
NH4HCO3.NH2COONH4, that releases ammonia, in sal volatile, smelling salts).
Ammonium carbonate is a white powder and is fairly soluble in water to form a weak alkali.

Ammonium chloride
Ammonium chloride, invisible writing ink (secret writing inks): 3.2.5.5
Ammonium chloride, Leclanché cell, dry cell, electric torch (flashlight) battery: 33.88
Ammonium chloride smoke screen: 3.33.6
Ammonium chloride, soldering flux: 2.33, (See: 2.)
Common ion effect in ammonium chloride solution: 17.5.5.6
Decomposition of ammonium chloride: 3.30.15
Fireproof cloth: 3.5.11
Heat ammonium chloride crystals: 8.4.1
Heat-sensitive paper, cobalt (II) chloride, ammonium chloride (sal ammoniac): 5.3.10
Hydrolysis of ammonium chloride: 12.10.3.2
Hydrolysis of sodium carbonate: 12.10.3
Low cost preparation, drops of muriatic acid with ammonia solution, until red to litmus paper
Prepare ammonium chloride sunbeam mists: 7.8.2.1
Prepare nitrogen gas: 3.46 (See: 1.)
Thermal dissociation of ammonium chloride, effect of temperature: 17.5.5.5

Ammonium chlorate
Ammonium chlorate, NH4ClO3, Toxic if ingested, Explosive, Not permitted in schools

Ammonium chloride, NH4Cl, sal ammoniac, Harmful if ingested
Ammonium chloride, NH4Cl, For 5 M solution, 270 g in water
Ammonium chloride, Solution < 20%, Not hazardous
Ammonium chloride
Ammonium chloride, NH4Cl, salmiac, sal ammoniac, colourless, odourless, cubic crystals or crystal mass, white granular powder,
sublimes without melting, weakly hygroscopic, saline taste (soldering flux, dry cell flux in torch battery), the mineral occurs in burning
coal piles and volcanoes.

Ammonium copper (II) chloride, tetramine copper (II) chloride
Tetramminecopper (II) chloride, Cu(NH3)4Cl2, ammonium cupric chloride, Harmful if ingested, skin irritant

Ammonium copper (II) sulfate hexahydrate (NH4)2Cu(SO4)2.6H2O
Ammonium cupric sulfate, diammonium copper (II) sulfate (VI)-6-water, Cu(NH3)4SO4.H2O, in fire extinguishers, Environment danger

Tetraamminecopper (II) sulfate, Tetraamminecopper (II) sulfatemonohydrate, cupraammonium (II) sulfate, [Cu(NH3)4(H2O)n]SO4,
dark blue solid, used in rayon production

Ammonium dichromate, (NOT "ammonium bichromate")
Ammonium dichromate (NH4)2Cr2O7, ammonium dichromate (VI)
Ammonium dichromate, powder, solid, Highly toxic if ingested, Corrosive, Oxidizing (OXD 1439)
Ammonium dichromate, solid, Toxic, Corrosive, Oxidizing (OXD 1439)
Ammonium dichromate, Solution < 0.5%, Not hazardous
Decomposition of ammonium dichromate: 3.30.14
Ammonium dichromate (NH4)2Cr2O7, ammonium bichromate, orange-red monoclinic crystals, heat decomposes,
(Not "ammonium bichromate").
The hazardous properties of this salt are similar to those of other soluble chromate and dichromate salts.
Ammonium dichromate, along with other yellow chromate and orange dichromate salts is believed to be carcinogenic.
An ammonium dichromate is unusual in that it undergoes an exothermic decomposition on heating to form green chromium (III) oxide, nitrogen gas and water.
Start the reaction with a lighted match.
The reaction continues because it is exothermic.
This reaction is NOT dangerous if only small quantities of material are used.
The reaction is dangerous if particles of undecomposed ammonium dichromate are projected into the air and inhaled.
Ammonium dichromate is often used in "volcano" experiments.

Ammonium iron (III) sulfate, iron (III) ammonium sulfate
Ammonium iron (III) sulfate, NH4Fe(SO4)2.12H2O, iron (III) ammonium sulfate, ferric ammonium sulfate (FAS), iron alum: 12.1.6
Ammonium iron (III) sulfate, diamond-shaped crystals, similar to potash alum and chrome alum, can be grown on a piece of cotton
Ammonium iron (III) sulfate, iron alum: 12.1.6
Prepare ferric tannate with tea leaves: 16.8.2 (See 4.)

Ammonium molybdate
Ammonium molybdate (NH4) 6Mo7O24.4H2O, or H24Mo7N6O24, Irritant, Harmful if ingested: 5.4.1
Ammonium molybdate (VII) 4-water, powder, ammonium paramolybdate
Ammonium molybdate catalyst, Hydrogen peroxide with sodium thiosulfate: 17.3.1.5
Ammonium molybdate, Tests for phosphates: 12.11.5.15
Prepare ammonium molybdate solution: 5.4.1

Ammonium nitrate
Ammonium nitrate, NH4NO3, (OXD 1942), Toxic if ingested
Ammonium nitrate, colourless crystals, soluble in water and ethanol, nitrate of ammonia garden fertilizer, in explosives
Ammonium nitrate must not be mixed with diesel oil to make an explosive mixture.
Low cost: fertilizer from garden supplies store, locate storage of small amounts away from sources of heat, fire or explosion and away
from other chemicals
Ammonium nitrate cold pack: 14.2.4
Movement of copper ions in ammonium nitrate solution: 3.4.3
Nitrates (hazards): 3.7.10
Prepare ammonium nitrate: 3.33.7

Ammonium oxalate, C2O4(NH4)2.2H2O, C2H8N2O4 (NH4)2C2O4), ammonium oxalate monohydrate,
ammonium ethanedioate-1-water, colourless, odourless, rhombic crystals or white granules, if heated decomposes before melting, in
kidney stones, guano
For 0.1 M solution, 16 g in 1 L water, Harmful if ingested

Ammonium perchlorate, NH4ClO4
Colour-white solid, powerful oxidizer, dangerous rocket propellent, , Not permitted in schools

Ammonium persulfate
Ammonium persulfate (NH4)2S2O8, ammonium peroxydisulfate, solutions < 25%, may be used for etching of copper and printed
circuit boards.
Solid dust may damage intestinal tract and cause allergy reaction, so use safety glasses.
Ammonium persulfate (NH4)2S2O8, ammonium peroxydisulfate, Toxic if ingested
Ammonium persulfate, Solution < 25%, Toxic if ingested
Solid dust may damage intestinal tract and cause allergy reaction.
Use safety glasses.
Ammonium persulfate, Etchants: 7.9.20.1
Ammonium persulfate, Persulfate-iodide clock reaction: 17.1.10

Ammonium phosphate, (NH4)3PO4, triammonium phosphate (V)-3-water, ammonium phosphate tribasic, nitrogen and phosphorus
garden fertilizer, flame retardant, added to baking powders to promote yeast growth
E342 Ammonium phosphate (emulsifier, stabilizer)
See diagram 3.1.2.6a: Matchbox

Ammonium sulfate
Ammonium sulfate, For 0.1 M solution, 13.2 g in 1 L water
Ammonium sulfate (NH4)2SO4, colourless, odourless, rhombic crystals or white granules, soluble in water but not ethanol,
decomposes above 280oC, sulfate of ammonia garden fertilizer, E517, cakes when stored, mascagnite mineral.
Ammonium sulfate (NH4)2SO4, sulfate of ammonia, analytical reagent, molecular weight 132.13, Harmful if ingested
Straight fertilizers, simple fertilizers, NPKS: 6.17.1.3
Ammonia with sulfuric acid, acid-base neutralization: 12.8.1
Heat substances that decompose and lose mass when heated: 3.30.0
Prepare ammonium sulfate by neutralization: 12.14.1

Ammonia
Ammonia, aqueous 28% to 30%, aqueous ammonia, aqua ammonia, ammonia water
Anhydrous ammonia
"Ammonia (total)"' refers to the mixture of ammonia (NH3) and the ionized form (NH4+).
Ammonia is less dense than air.
Ammonia solution is a weak electrolyte, so the properties of the molecules and the ions in the solution affect its properties.
The NH3 compound is the volatile, potentially hazardous, substance present in the mixture.
Ammonia is used in household and industrial cleaners, bleaching agents and disinfectants, and in the preparation of synthetic fibres,
(e.g. nylons), plastics and explosives, resins, medicines, fertilizers, fuel cells and in refrigeration.
Ammonia is a colourless gas with a distinct, pungent odour that is distinctive of drying urine.
Ammonia is easily liquefied under pressure.
Ammonia is alkaline and is corrosive to copper.
Ammonia reacts strongly with oxidizers, acids, halogens, and attacks copper, aluminium, silver, zinc and their alloys, and some plastics.
Ammonia is very soluble in water, chloroform and ether, soluble in alcohol and is a good solvent.
Ammonia is toxic if at high levels with increased pH to animals, birds, and fish caused by the NH3.
Ammonia is formed naturally by the decomposition of urine and manure.
Ammonia solution, ammonium hydroxide, NH3 (weak ammonia, about 10%, is sold as a household cleaner)
Ammonia is an invisible, extremely irritating gas with a choking smell and is flammable in the presence of sufficient oxygen.
Do not prepare ammonia in an open room but use a fume cupboard.
Ammonia is less dense than air.
Ammonia solution is a weak electrolyte so the properties of the molecules and the ions in the solution affect its properties.
Concentrated ammonia solution forms ammonia gas whenever the container holding it is opened.
Ammonia is extremely irritating to the nose and lungs.
If ammonia solution is spilt in a fume cupboard, evacuate the area until the ammonia fumes have dispersed.
Do not allow ammonia solution to contact the skin.
Do not add concentrated ammonia to solid iodine because a black solid, called touch powder, NI3NH3, forms, and, if dry, the slightest
friction causes it to explode.
Do not add concentrated ammonia to bleach or bleaching powder because nitrogen trichloride, NCl3, may form, a violently unstable
liquid that may explode.
Common name: Household ammonia, 10% solution, ammonium hydroxide, NH4OH, is a strong solution of the gas used for cleaning.
Common name: Strong ammonia is a 27% solution.
"Cloudy ammonia" contains powdered soap in addition to ammonia.
Ammonia solution is used for neutralizing acids and for precipitating hydroxides of metals, usually as jelly-like precipitates, formed
when ammonia is added to solutions of soluble compounds of the metals, e.g. alum (aluminium potassium sulfate), iron alum,
(iron (III) ammonium sulfate), magnesium sulfate, and zinc sulfate.
Household ammonia is far too strong for most experiments.
Prepare a dilute solution by adding about five parts of water to one part of the strong solution.
The gas dissolves in water to form an alkali.
Ammonia solution is used for neutralizing acids and for precipitating metal hydroxides, usually as jelly-like precipitates when ammonia
is added to solutions of soluble compounds of the metals, e.g. alum, ferrous sulfate, iron alum, magnesium sulfate, zinc sulfate.
Household ammonia is far too strong for most school experiments so prepare a dilute solution by adding about five parts of water to
one part of household ammonia.

Ammonia solution
Ammonia solution, NH3 (aq) (COR 2672) (28%), 18 M
See: 12.11.3.10.2: Tests for ammonium radical, NH4+, free and combined ammonia, Nessler's reagent
Use in a fume cupboard.
Use eye and skin protection.
Do not mix ammonia with halogens, F, Cl, Br to avoid explosive reaction.
Ammonia with solid iodine forms a highly unstable nitrogen triiodide complex, touch powder.
Do not make touch powder.
Solution of ammonia in water, NH3 (aq), colourless liquid, suffocating, pungent odour, absorbs CO2 from air < 10% actual NH3,
"880" ammonia concentrated ammonia solution, 15.5 M, 880 ammonia solution, 0.88 gm cm-3, aqua ammonia, ammonia water,
ammonia hydrate, spirits of hartshorn, Liq. Amm. Fort. 16 mol per mL, "cloudy ammonia" contains soap solution, E527,
dilute ammonia solution, 6 M, needs cool storage, alkaline solution.
Many ammonia solutions sold in supermarkets are 10% aqueous ammonia, about 5.8 M), but some contain soap.
It cannot be concentrated by distillation.
Ammonia, NH3 (aq), or NH4OH, For 2 M solution., dilute 330 mL of 10% solution in 1 L water
ammonia solution (10% ammonia solution), 5.3.4
ammonia solution 3 M: dilute 200 mL (28%), 14.8 M concentrated solution to 1 litre of water
ammonia solution 4 M: dilute 220 mL (28%), 18 M concentrated solution to 1 litre of water ("ammonium hydroxide"),
ammonia solution 4 M: Dilute 220 mL (28%), 18 M concentrated solution to 1 litre of water ("ammonium hydroxide"),
ammonia solution 3 M: Dilute 200 mL (28%), 14.8 M concentrated solution to 1 litre of water,
ammonia solution, concentrated / 35% / 0.88 g mL-1, 18 M, 35%, 110 mL of concentrated solution for 1 litre of 2 M solution.
Ammonia [Not "ammonium hydroxide, NH4OH", ammonia solution shown as NH3 (aq), because "(NH4+), " ions and "(OH-), " ions
can be detected, but "NH4OH" cannot be detected.]
However, an equation to show that ammonium hydroxide is a weak base with the equilibrium well to the left is as follows:
NH4OH (aq) <=> NH4+ (aq) + OH- (aq)]

3.33.01 Prepare ammonia, Haber process
Ammonia is produced industrially by the Haber process with a catalyst, with direct synthesis at high pressure and temperature 45oC.
Cloudy ammonia is clear ammonia solution with soap added in memory of the days before the Haber Process when ammonia was
made from coal tar and had cloudy impurities.
It may be sold as ammonia solution 5-18 M, 10-35%, ammonium hydroxide, household and trade use.
N2 (g) + 3H2 (g) < = > 2NH3 (g) + energy released

3.33.1.1 Concentrated hydrochloric acid test (hydrogen chloride test), for ammonia
Dip one end of a glass rod into concentrated ammonia solution and one end of another glass rod into concentrated hydrochloric acid.
Bring the two ends close to each other but do not let them touch.
A blue-white smoke of ammonium chloride forms.
NH3 (g) + HCl (g) --> NH4Cl (s)

3.33.1.2 Odour test for ammonia
See diagram 1.13: Smelling test
Ammonia solution is a weak electrolyte.
When a strong electrolyte dissolves in water, it almost completely dissociates into ions.
Weak electrolytes do not dissociate so much.
Water is a very weak electrolyte.
The properties of weak electrolytes are affected both by the properties of the molecules in the solution and the properties of the ions
in the solution.
1. Note the odour of dilute aqueous ammonia solution.
Shake the solution vigorously and smell by very cautious smelling, as in the diagram.
Use very small amounts of reacting chemicals.
Do not inhale directly from a test-tube but fan the air above the test-tube towards you.

2. Put a drop of aqueous ammonia solution in a test-tube with a stopper.
Shake the test-tube and warm it with the hands.
Note the pungent odour of ammonia.
Be careful! Do not inhale gases directly from the test-tube!
Fan the gas towards the nose with the hand and sniff cautiously.
If you detect no odour, move closer and try again.

3. Add powdered wood charcoal.
Shake the test-tube and smell the contents again.
Filter the mixture.
Heat the charcoal and note the absence of the pungent odour of ammonia.

3.33.1.3 Litmus tests for ammonia
Ammonia dissolves in water to form a weak base that turns moist red litmus paper blue.
1. Test for ammonia with damp red litmus paper
2. Wet red litmus paper with deionized water and stick it to the concave side of a large watch glass.
Put 1 mL of 0.1 M NH4Cl in a smaller watch glass or a smaller diameter beaker, heat it then add 6 M NaOH.
Cover the smaller watch glass or beaker with the inverted large watch glass.
Ammonia vapour from the smaller watch glass or beaker will turn the red litmus blue.

3.33.1.4 Solubility tests for ammonia
Ionization reaction, Kb = 1.8 × 10-5
NH3 + H2O <--> NH4+ + OH-
1. Dip the open end of a test-tube containing ammonia under water.
The test-tube fills with water.
Ammonia is the most soluble of all gases.
Ammonia dissolves in water to form ammonia solution, NH3 (aq).
Do not call it "ammonium hydroxide" because while "NH4+" ions and "OH-" ions can be detected, "NH4OH" cannot be detected.
So a reaction with ammonia solution is written as follows:
X+ (aq) + OH- (aq) --> XOH (s)
or as molecules:
XCl (aq) + NH3 (aq) + H2O (l) --> XOH (s) + NH4Cl (aq).

2. Show the extreme solubility of ammonia
Remove the stopper from a test-tube of ammonia and quickly put your thumb or finger over the mouth of the test-tube.
Invert the test-tube of gas in a dish of water, removing your thumb only when the mouth of the test-tube is under the water.
Describe what you see.
The solution made in this rushes up into the test-tube.
Ammonia is so soluble that it dissolves almost at once in the water at the mouth of the test-tube.
Atmospheric pressure therefore forces the water into the empty test-tube.
Ammonia has a greater solubility than hydrogen chloride.

3.33.1.5 Sodium bicarbonate test for ammonia
See diagram 1.13: Smelling test
Add solid sodium bicarbonate and heat until you can smell the ammonia given off.

3.33.1.6 Ammonia fountain test
See diagram 3.2.37.2: Fountain experiment
1. Heat the end of a delivery tube and draw it out to form a fine jet.
Fill a flask with ammonia and close the flask with a one-hole stopper with a delivery tube.
Add litmus to acidified water in a beaker.
Warm the flask gently to expand the gas and then hold the flask upside down with the lower end of the delivery tube in the acidified
water.
Water soon sprays into the flask through the fine jet as the ammonia dissolves in the water and the pressure of ammonia in the flask
decreases.
The litmus in the water changes from red to blue.
NH3 (g) + H2O (l) < = > NH3 (aq) + H+ + OH- (aq)
or
NH3 (g) + H2O (l) < = > NH4+ (aq) + OH- (aq)

2. Fill a beaker with litmus solution.
Add a few drops of acid solution to the litmus in the cup until the colour just changes to red.
Fit a glass jet tube into the stopper of a flask.
Remove the stopper and jet, and start filling the dry flask with ammonia.
When the flask is full of gas, replace the stopper and jet, and quickly invert the flask with the other end of the jet tube in the litmus
solution.
With the spirit burner at a safe distance, pour a finger width of methylated spirit on the flask and blow on it.
This causes the spirit to evaporate and thereby cool the flask and the gas inside it.
The contraction of the gas reduces its pressure, and atmospheric pressure forces litmus solution up the glass tube and out of the jet.
The fountain from the jet suddenly increases and the litmus changes colour.
The fountain from the jet suddenly increases for the reason given above.
The red litmus solution turns blue, because the water in the litmus solution turns part of the ammonia into the alkali ammonium
hydroxide.

3. Gently heat in a bath of warm water 100 mL of concentrated ammonia solution in a 250 mL conical flask fitted with a rubber
stopper and a short glass tube.
Collect the ammonia gas produced in an inverted round bottom flask, by displacement of air.
Ammonia is less dense than air.
When the round bottom flask is full of ammonia, insert a rubber stopper fitted with a short glass tube tapered inside to a narrow jet.
Immerse the external end of the glass tube in water.
Ammonia will dissolve in the water in the tube, reducing the pressure inside the flask.
Atmospheric pressure will then force water into the tube, creating a jet of water, called the ammonia fountain.
Add phenolphthalein to the water to make the reaction more spectacular.
Demonstrators and observers must wear safety glasses.

3.33.1.7 Nessler's reagent test for ammonia
Nessler's reagent
Nessler's reagent is not permitted in some school systems because it contains mercury.
Add Nessler's reagent to the original solution.
A brown colour indicates the presence of ammonium ion.
The test is very sensitive, so the test solution must not contain any NH4+ added during the analysis.

3.33.1.8 Tests for ammonium compounds
See diagram 1.13: Smelling test
Add sodium hydroxide solution, then heat, and note if ammonia gas is produced.

3.33.2.1 Prepare insoluble hydroxides with ammonia solution, double decomposition
Dissolve ammonia gas in water to form ammonia solution, ammonium hydroxide.
Prepare dilute solutions of alum (mainly aluminium sulfate), magnesium sulfate, and manganese sulfate.
Add ammonia solution to each prepared solution.
Note the colours of the insoluble hydroxides formed
Aluminium sulfate + ammonium hydroxide > aluminium hydroxide (faintly white) + ammonium sulfate
Magnesium sulfate + ammonium hydroxide > magnesium hydroxide (white) + ammonium sulfate.
Manganese sulfate + ammonium hydroxide > manganese hydroxide (white brown) + ammonium sulfate.
These double decomposition reactions occur because one of the products is insoluble.

3.33.3 Ammonia solution in a neutralization reaction
Add a finger width of dilute sodium hydrogen sulfate solution in a test-tube, add a few drops of litmus solution.
Gradually add ammonia solution to the test-tube, with shaking, using the dropping pipette, until one drop just changes the colour of the
mixture to purple blue.
The ammonium hydroxide in the ammonia solution reacts with the sulfuric acid in the sodium hydrogen sulfate solution.
As ammonia solution is added, the more acid is destroyed, until a point is reached when there is no more acid and no extra ammonia
has been added.
The alkali has exactly neutralized the acid (when the drop just changed the colour of the litmus), forming a salt (ammonium sulfate)
and water.
Ammonium hydroxide + sulfuric acid --> ammonium sulfate + water.

3.33.4 Ammonia with copper sulfate solution
Add a finger width of ammonia solution to half a test-tube of copper sulfate solution.
A double decomposition reaction occurs as you would expect.
Note the pale blue solid formed?
add more ammonia solution, and shake, until the solid disappears.
Try the experiment again, making the copper sulfate solution so dilute that the blue colour is scarcely visible, and adding all the
ammonia at once.
The pale blue solid is copper hydroxide.
When more ammonia solution is added, it reacts with the copper hydroxide, forming a complex copper-ammonia compound, which
has a deep blue colour.
This blue colour appears even with very dilute solutions of copper compounds, and so is a useful test for them.

3.33.5 Ammonia with cobalt chloride solution
To a dilute solution of cobalt chloride add a finger width of ammonia solution.
Describe what happens.
A blue-green precipitate a complex cobalt-ammonia compound forms.

3.33.6 Ammonium chloride smoke screen
Before starting the experiment, make sure the laboratory is well ventilated. In one test-tube place a finger width of a mixture of sodium chloride (salt) and sodium hydrogen sulfate, and in another a finger width
of a mixture of ammonium chloride and calcium hydroxide.
Heat both tubes at the same time, as in the diagram.
Hold the mouths of the test-tubes together so that the two colourless gases can combine.
Be careful! Do not inhale the gases and fumes!
The gases are hydrogen chloride and ammonia.
The gases, hydrogen chloride and ammonia combine, forming the solid salt, ammonium chloride, tiny particles of which form the white
smoke.

3.33.7 Prepare ammonium nitrate
1. Ammonia reacts with nitric acid to form ammonium nitrate.
However, this is a dangerous reaction.
NH3 (aq) + HNO3 (aq) --> NH4NO3 (aq)
Ammonia with nitric acid --> ammonium nitrate

2. Dissolve 138 g sodium bisulfate (sodium hydrogensulfate, swimming pool chemical) in 300 mL water.
Dissolve 85 g sodium nitrate in a minimum amount of water, then mix the two solutions.
Add ammonia solution until pH >7.
Boil the solution until sodium sulfate crystals form in the bottom of the pan.
The decant the solution, leave to cool in a refrigerator to remove all the sodium sulfate as crystals.
Separate sodium sulfate crystals with filter paper or paper towels or coffee filters.
Heat the ammonium nitrate solution to evaporate and leave behind any sodium sulfate.
Dissolve the ammonium nitrate solution in methanol then leave to evaporate the methanol.
Sodium sulfate is not soluble in methanol.
ammonia + sodium bisulfate + sodium nitrate --> sodium sulfate + ammonium nitrate
Sodium bisulfate is used to reduce ammonia produced during animal production.

3.42.1.6 Tests for hydrogen chloride with ammonia solution
Hold a piece of cotton wool soaked in ammonia solution, NH3 (aq) ("ammonium hydroxide") at the mouth of a receiving test-tube,
and note the white cloud of ammonium chloride above the hydrochloric acid.

13.6.5 Tests for hydroxyl ions (hydroxide ions), ammonia solution
Be careful! The odour of ammonia indicates the presence of ammonia molecules in the solution.
Test for the presence of hydroxyl ions.
Add drops of iron (III) chloride to aqueous ammonia solution.
The reaction forms a brown precipitate that indicates the presence of hydroxyl ions in the solution.

13.6.6.1 Catalytic oxidation of ammonia, with red-hot platinum wire
See diagram 13.6.6.1: Oxidation of ammonia with platinum wire
Be careful! Do this experiment in a fume cupboard!
Use concentrated aqueous ammonia solution in a test-tube.
Heat a spiral of platinum wire until it becomes red-hot.
Insert the wire in the test-tube above the solution.
The wire stays red hot and the reaction forms nitrogen monoxide that reacts with oxygen in the air to form nitrogen dioxide.
4NH3 (g) + 5O2 (g) --> 4NO (g) + 6H2O (g)
2NO (g) + O2 (g) --> 2NO2 (g)

13.6.6.2 Catalytic oxidation of ammonia, with chromium (III) oxide
See diagram 13.6.6.2: Oxidation of ammonia with chromium (III) oxide catalyst
Be careful! Do this experiment in a fume cupboard!
Chromium (III) oxide may be carcinogenic Use chromium (III) oxide as catalyst.
Put 0.5 g of ammonium dichromate (VI) in an evaporating dish.
Heat with an alcohol lamp until the dichromate starts to decompose.
Move the lamp away and the dichromate keeps on decomposing.
Wait until the decomposition is completed.
Heat the obtained chromium (III) oxide again to dry it thoroughly.
To make a catalyst tube, put the freshly prepared chromium (III) oxide in a dry glass tube and squeeze a little glass wool on both sides.
Be careful! Do not touch glass wool with the fingers! Do not breathe in the fibres!
Heat the catalyst tube for about 3 minutes to raise the temperature of the catalyst to above 500oC.
By using an air pump, send slowly a stream of air through the concentrated aqueous ammonia solution contained in a conical flask, and
then to pass the air ammonia mixed gas over the heated catalyst.
When the catalyst becomes red hot, stop heating and continue sending the mixed gas.
Prepare the gas coming from the catalyst tube pass through a gas washing bottle of concentrated sulfuric acid to remove the excess
ammonia and the water produced in the reaction.
A brown-red gas appears in the collecting conical flask.
Into this flask pour a little deionized water, shake, then add a few drops of litmus makes the solution turn red to prove that nitric acid
forms in this flask.
4NH3 (g) + 5O2 (g) --> 4NO (g) + 6H2O (g)
2NO (g) + O2 (g) --> 2NO2 (g)

13.6.7 Reduce copper (II) oxide to copper with ammonia
See diagram 13.6.7: Reduce copper (II) oxide
Pass dry ammonia over copper (II) oxide in a heated hard glass tube.
The ammonia reduces the black copper (II) oxide to brown copper and is oxidized to nitrogen gas.
2NH3 (g) + 3Cu (s) --> 3Cu (s) + 3H2O (l) + N2 (g)

13.6.8 Ammonia with copper sulfate
Put 1 cm of copper sulfate into a test-tube and add dilute ammonia solution to the tube drop by drop.
After adding each drop shake the tube.
At first a light blue precipitate forms, but as more ammonia is added the precipitate will dissolve giving a deep royal blue solution.
The colour is caused by the formation of cuprammonium sulfate, tetraamminecopper(II) sulfate, [Cu(NH3)4(H2O)n]SO4, a metal
complex, related to Schweizer's reagent, tetraamminediaquacopper dihydroxide, [Cu(NH3)4(H2O)2](OH)2].
To obtain the compound in solid form add a little methylated spirit to the tube.
A violet blue precipitate forms.
If the precipitate is filtered it gives an excellent flame test for copper when introduced into a flame on the end of a wet spill or match.
It can be prepared by adding concentrated solution of ammonia to a saturated aqueous solution of copper sulfate then precipitate the
product with ethanol.
The deep blue crystals may hydrolyse and release ammonia if left in the air.

3.33.0 Prepare ammonia gas
| 3.32.0 Prepare gases with a gas generation apparatus
| See diagram 3.2.37.1: Prepare ammonia
| See diagram 1.13a: Simple fume hood
| See diagram 3.33.2: Fountain experiment: A ammonia, B acidified water
Be careful! Prepare ammonia gas only in a fume hood or fume cupboard!
1. Put a mixture of calcium hydroxide and ammonium chloride into a test-tube to a depth of 4 cm.
Fill a U-tube with lumps of calcium oxide mixed with cotton wool.
The cotton wool is to prevent blocking of the U-tube.
Gently heat the test-tube.
The calcium oxide is to dry the ammonia gas.
Collect the less dense gas (0.769 kg / m3), by downward displacement of air.
Test whether the receiver test-tube is full by holding a piece of moist red litmus paper at the opening.
Ammonia gas turns red litmus blue.
Collect test-tubes of ammonia gas and apply stoppers.
2NH4Cl (aq) + Ca(OH)2 (s) --> 2NH4OH (s) + CaCl2 (aq),
then NH4OH (s) --> NH3 (g) + H2O (l)
2NH4Cl (aq) + Ca(OH)2 (s) --> 2NH3 (g) + CaCl2 (aq) + 2H2O

2. Prepare ammonia with ammonium chloride and sodium carbonate
See diagram 1.13: Smelling test
Put 5 g of ammonium chloride (sal ammoniac) in 2 cm depth sodium carbonate (washing soda) solution.
Heat the test-tube.
Test for ammonia gas and with wet red litmus paper.

3. Prepare ammonia with ammonia solution and sodium hydroxide.
Add 15 g of granular sodium hydroxide to 30 mL of concentrated ammonia solution contained in a conical flask.
Immediately fix in the flask a stopper with a straight delivery tube inserted in it.
A large quantity of ammonia forms quickly.
Simultaneously, the temperature of the reaction increases and froth seethes inside the flask.
NH4Cl (aq) + NaOH (s) --> NaCl (s) + H2O (l) + NH3 (g)

4. Heat a finger width of ammonium chloride mixed with an equal amount of calcium hydroxide in a large test-tube fitted with stopper
and delivery tube.
The test-tube should be inclined slightly, otherwise the water formed in the reaction can flow back into the hot end of the tube.
Collect the gas by passing it upwards into another test-tube, since ammonia is less dense than air.
A piece of moist red litmus paper, held at the mouth of the container, will show when each is full.
Insert a stopper and store the test-tubes of ammonia.

5. Mix a finger width of calcium hydroxide with an equal quantity of ammonium chloride on a sheet of paper.
Rub the mixture with the glass rod, and notice the smell of ammonia gas evolved.
Hold a piece of moistened red litmus paper over the mixture.
The litmus turns blue.
Ammonia is a gas which, when moist, has alkaline properties.

6. Prepare ammonia with sodium hydroxide and ammonium salts.
Moisten a salt spoon of ammonium chloride, carbonate, or sulfate with drops of caustic soda solution.
Ammonia gas forms.
It can be tested by smell and by the turning blue of damp red litmus paper.

7. To prepare dry ammonia gas attach an U-tube packed with calcium oxide granules between the horizontal Pyrex test-tube and the
vertical inverted collection test-tube.
Heat a mixture of ammonium chloride and calcium hydroxide solids in the test-tube and collect the pungent ammonia by
upward delivery.
It has a very pungent odour and turns red litmus blue.

Hartshorn
Distillation of ground deer antlers forms "oil of hartshorn", or "salt of hartshorn", ammonium carbonate, used in smelling salts.
Aqueous solution of ammonia called "spirit of hartshorn".