useful to teach secondary level students

1. TEACHING SLIDES FOR
AMMONIA

2. INTRODUCTION
NAME OF THE GAS-AMMONIA
MOLECULAR FORMULA-NH3
FIRST PREPARED BY-JOSEPH PRIESTLEY
MOLECULAR STRUCTURE

3. METHODS OF PREPARATIONS
1. By heating ammonium salts.
(NH4)2CO3 --- NH3 + H2O +CO2
2 .By heating ammonium salts with strong bases.
NH4Cl + NaOH --- NaCl + H2O +NH3
(NH4)2SO4 + KOH --- K2SO4 + H2O + NH3

4. LABORATORY PREPARATION METHODS
APPARATUS REQUIRED
1.HARD GLASS TEST TUBE
2. IRON STAND
3. DELIVERY TUBE
4. LIME TOWER
5. GAS JAR
6 . BURNER
https://www.youtube.com/watch?v=
rwwgZnRYUis

5. INDUSTRIAL METHOD OF PREPARATION
Ammonia can be manufactured industrially in large scale
by using Haber's synthesis process. The process to manufacture
ammonia by compressing nitrogen and hydrogen at 250 atmospheric
pressure and heating at 500 0C in presence of iron catalyst and
molybdenum as promoter is called Habers process. The ratio of
nitrogen and hydrogen is 3:1.
The condition required for Haber's process are given below.
1. The ratio of nitrogen and hydrogen os 3:1.
2. The temperature should be 500 0 C.
3. The pressure should be more than 250 atmospheric pressure.
4. The iron powdered should be the catalyst.
5. Molybdenum should be the promoter.
N2 + 3 H2 --- 2NH3 ( Fe catalyst/ Mo promoter/ 250 atm
pressure/ 500 0 C temperature ).
https://www.youtube.com/watch?v=Ou2U0pkCC88

6. TEST OF AMMONIA
1. It has choking smell or pungent smell which can be test
by smelling directly.
2. Ammonia forms a dense whit cloud of NH4Cl with HCl.
3. When moist red litmus is exposed to ammonia turn blue.
4. https://www.youtube.com/watch?v=CZSl9gdouek
5. https://www.youtube.com/watch?v=OxhWwPMlgdA

7. PHYSICAL PROPERTIES OF AMMONIA GAS
1. The density of ammonia is lower than that of air.
2. It neither burns itself nor supports burning.
3. It is colorless and tasteless gas with a pungent odor that
brings about tear onto eyes.
4. It is extremely soluble in water.
5. It can be liquefied at -33.40C and solidified at -780 C .
6. It turns wet red litmus into blue one.

8. CHEMICAL PROPERTIES OF AMMONIA GAS
1. Ammonia is highly soluble in water and its solution is called
ammonium hydroxide or liquor ammonia.
NH3 (g) + H2O ( l ) -------- NH4OH ( aq )
2. It reacts with acid to form salt.
NH3 ( g ) + HCL ( g ) ---------- NH4CL ( s )
NH3 ( g ) + HNO3 ( aq ) ------- NH4NO3 ( aq )

9. CHEMICAL PROPERTIES OF AMMONIA GAS
3. Ammonia solution in water reacts with acid to form salt and
water.
NH4OH( aq ) + HCL( aq ) ---------- NH4CL ( aq ) + H2O ( l )
2NH4OH( aq ) + H2SO4( aq ) --------- (NH4)2SO4(aq) + 2H2O( l )
NH3OH( aq ) + HNO3 ( aq ) ----------- NH4NO3( aq ) + H2O( l )
4. When ammonia reacts with carbon dioxide at the temperature
of 1500 0 C under high pressure , it forms urea.
CO2 ( g ) + 2NH3( g )15000 C
----------- pressure NH2-CO-NH2 ( aq ) + H2O( l )

10. CHEMICAL PROPERTIES OF AMMONIA
GAS
5. Ammonia reacts with hydrogen chloride and produces dense
white fumes of ammonium chloride.
NH3 ( g ) + HCl ( g ) ------ NH4Cl
6. Ammonia gas produces nitrogen gas and water on
burning in air.
4NH3 + 3O2 --------- 2N2 + 6H2O

11. SOME USES OF AMMONIA GAS
1. Ammonia gas is used for making nitrogenous fertilizer like urea,
ammonium sulphate , etc.
2. It is used in manufacturing nitric acid.
3. It is used in plastic industries.
4. It is used to make washing soda.
5. It is used in the development of “blue prints” of maps.
6. It is used in the preparation of artificial silk.
7. Aqueous ammonia is used as a cleansing agent as it can dissolve
grease.

12. GIVE REASONS
• Ammonia is covalent compound. –formed by sharing electron between nitrogen
and hydrogen.
• Hard glass test tube is slanted. - to prevent the cracking of test tube due to water.
• Lime tower is used in manufacturing ammonia.- to absorb water vapors
• Moist red litmus is used to test. – being basic nature red changed in to blue.
• Gas jar is kept inverted collecting ammonia.- lighter than air.
• water fountain is possible.- ammonia reacts with water , pressure decreases in flask
and water raised up as fountain.
• Ammonia does not formed directly in atmosphere.- not suitable temperature and
pressure.

13. WORDS TO REMEMBER
Sal ammoniac - it is a rare naturally occurring mineral composed of ammonium chloride, NH4Cl.
It forms colorless, white, or yellow-brown crystals in the isometric-hexoctahedral
class. It has very poor cleavage and a brittle to conchoidal fracture.
Catalyst - a substance that increases the rate of a chemical reaction without itself undergoing
any permanent chemical change.
Promoter – the chemical which promoters the reactions.
Haber's process – the process to manufacture ammonia by compressing nitrogen and hydrogen at 250
atmospheric pressure and 500 0 C in presence of iron catalyst and molybdenum as promoter.
Blue print – the image formed in paper from drawing of plastic by using liquid ammonia .

14. DEMONSTRATING SOLUBILITY
OF AMMONIA BY FOUNTAIN
EXPERIMENT
Fill a flask with
ammonia gas and close it
with a cork carrying a
straight glass tube. Dip
the lower end of the
tube in a trough of
water containing a
little phenolphthalein
indicator.
https://www.youtube.com/watch?
v=3CafICEol0A

15. THANK YOU
MEGHA NATH POUDEL
Pokhara -17, Mitrabandhumarga
Kaski ,Gandaki, Nepal ,061-460067