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Symbol: N
Molecular formula: N2
Valency: 3
Position in periodic table: Group-V A, Period-2nd
Electronic configuration: 2, 5 (1S2, 2S2 2P3)
Atomic number: 7
Atomic weight: 14
Molecular weight: 28 amu
Freezing point:- 210 °C
Boiling point: -196 °C


Nitrogen is found in both free and combined states. It occupies 78.07% by volume.

General methods of preparation of nitrogen gas

By heating copper in air:

Firstly, air is passed through lime water and then concentrated sulphuric acid to make the air free from carbon dioxide and moistures respectively. The air contains only nitrogen and oxygen which are passed over the heated copper wire as shown in the figure. Here copper combines with oxygen to make copper oxide and nitrogen gas passes over. This nitrogen can be collected by downward displacement of water.

By burning phosphorous in air:

Nitrogen gas can be prepared by burning phosphorous in air. A crucible with phosphorous is taken and allowed to float on water. Then phosphorous is burnt in crucible is covered with gas jar as shown in figure. The oxygen of the gas jar is consumed during the burning of phosphorous penta oxide is formed. The gas left in the jar is nitrogen.
4P + 5O2 → 2P2O5

By decomposition of compounds containing nitrogen

Like, when dilute solution of ammonium nitrite is heated, nitrogen gas is produced.
NH4NO2→ N2 +2H2O

Laboratory preparation of nitrogen gas

When the solution of sodium nitrite and ammonium chloride is heated they react together and liberate nitrogen gas.
NaNO2 + NH4Cl → NaCl + H2O +N2

Take a mixture of ammonium Chloride and Sodium nitrate in equivalent amount in a round bottom flask. Some water is added to make the solution of the mixture. Then the delivery tube is fitted with a round bottom flask with the help of a cork. The flask is heated gently with a source of heat. After that gas is produced by the reaction of chemicals and is collected in gas jar by downward displacement of water.


  • Ammonium chloride and sodium nitrite should not be used in solid form because ammonium chloride, being a sublimate, sublimes and escape in form of vapour on heating.
  • Apparatus should be made airtight.
  • Ammonium chloride and sodium nitrite should be taken in equivalent amount.

Test of nitrogen

When burning magnesium ribbon is inserted in a jar containing gas, if it burns continuously and forms magnesium nitride, it proves that gas is nitrogen.

Properties of nitrogen

Physical properties
  • It is neutral to the indicator.
  • It is non-combustible gas but it is combustion supporter.
  • It liquefies at -196°C and solidifies at -210°C.
  • Nitrogen gas in generally inert, nonmetallic, colourless, odorless and tasteless.
  • The atomic number of nitrogen is 7 and its atomic weight is 14.0067.
  • The density of nitrogen at 0oC is 1.251 grams/liter and its specific gravity is 0.96737.
  • Nitrogen forms trivalent bonds in most compounds.
Chemical properties
  • When a mixture of nitrogen and hydrogen is heated to about 500°C, at the atmospheric pressure of 200-900 atmosphere and in the presence of a catalyst finely divided iron and molybdenum, ammonia gas is liberated.
    N2 + 3H2 → 2NH3
  • When a mixture of nitrogen of nitrogen and oxygen is heated at 2000°C- 3000°C in electric arc, they combine together and give oxides of nitrogen.
    2N2 + O2 → 2N2O (Nitrous oxide)
    N2 + O2 → 2NO (Nitric oxide)
    N2 + 2 O2 → 2NO2 (Nitrogen dioxide)
  • Reactive metals like magnesium, calcium, aluminium etc. when burnt in nitrogen forms respective nitrides.
    3Mg + N2 → Mg3N2 (magnesium nitride)
    3Ca + N2 → Ca3N2 (calcium nitride)
    2Al + N2 → 2AIN (aluminium nitride)

Uses of nitrogen

  • It is used to manufacture explosive.
  • It is used for replacing fuel in fuel tanks in airplane.
  • It is used in filling electric bulbs

  • Nitrogen is an inert gas which constitutes about 78% by volume of the atmosphere.
  • Nitrogen gas is prepared in the laboratory by heating the mixture of ammonium chloride and sodium nitrite in the ratio of 1:1.
  • Nitrogen combines with hydrogen in 1:3 ratio to form ammonia gas.
  • Nitrogen is neither combustible nor a supporter of combustion.
  • Nitrogen gas is used to manufacture explosive.

Questions and Answers

Click on the questions below to reveal the answers

Nitrogen is the seventh element on the periodic table. It is located in period 2 and group 15.

Physical properties on nitrogen are:

1.Nitrogen is a colorless, odourless and tasteless.
2. It is slightly lighter than air.
3. It is very slightly soluble in water. etc.

Nitrogen is an inert gas which constitutes about 78% by the volume of the atmosphere.

We use nitrogen gas for:

1. manufacturing nitric acid.
2. Manufacturing of nitrogen rich fertilizer.
3. Nitrogen gas is used to manufacture explosive.

Nitrogen gas is prepare in the laboratory by heating the mixture of amoniumchloride and sodium nitrite in the ratio 1:1. NH4CI + NaNO2 --------> NaCI + N2 + 2H2O

  • How is nitrogen gas important for biologic process?

    It is a constituent of mineral
    It is a constituent of carbohydrate
    It is a constituent of fat
    It is a constituent of protein
  • What is not true about Nitrogen?

    It is inert
    It is less reactive and less stable than oxygen
    It is most widely occurring gas in nature
    It occurs in nature in free and bound state
  • What happens when Ammonium Chloride and Sodium Nitrite are heated together?

    It produces Nitrogen and Hydrogen gas
    It produces Hydrogen gas
    It produces Ammonium nitrate and Nitrogen gas together
    It produces Nitrogen gas
  • When liquid ammonia reacts with bleaching power it gives Nitrogen gas, water and ____?

  • What test confirms presence of ammonia gas?

    Burning candle shows blue color
    Burning candle extinguishes without giving a pop sound
    Burning candle burns more intensely
    Burning candle extinguishes giving a pop sound
  • Which is not property of nitrogen?

    it is neutral to indicators
    It is not combustible or supporter of combustion
    it is very reactive as it has double bonds
    It is colorless, tasteless and odorless
  • What is synthesized by Harber's process?

  • What does reaction of Calcium and Nitrogen give?

  • What is not use of nitrogen gas?

    Used in Airplanes to prevent planes from explosion
    Used in manufacturing of ammonia, chemical fertilizer, calcium cyanide
    Welding and cutting of metals
    filled in Electric lamps as it is inert in nature
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