About 5 g of sodium nitrite and 4 g of ammonium chloride is kept
in a clean round bottomed flask.
About 50 ml of water is kept in the flask and a solution is
prepared.
Apparatus are fitted as shown in the figure.
The solution is heated gently using a Bunsen burner.
Nitrogen gas is produced after the mixture is heated.
The produced nitrogen gas is collected in a gas jar by downward
displacement of water using a delivery tube.
Important Points
Apparatus should be fitted airtight and the mixture is heated
gently.
Solution of the mixture needs to be prepared before heating since
ammonium chloride undergoes sublimation at solid state.
Test of the Gas
A burning magnesium ribbon continues burning when inserted into
the jar containing nitrogen gas.
The magnesium ribbon finally turns into yellow powder (magnesium
nitride).
When some drops of water are added to the yellow powder, the smell
of ammonia is felt.
This confirms the presence of nitrogen in the gas jar.
Physical Properties of Nitrogen Gas
Nitrogen is colourless, odourless and tasteless gas.
It is lighter than air.
It is sparingly soluble in water.
Nitrogen gas is neutral in nature and does not affect litmus
paper.
It is neither combustible nor a supporter of burning.
It liquefies at about -196°C and solidifies at -210°C.
What Happens:
When the mixture is heated, nitrogen gas is produced. The gas
passes through the delivery tube and bubbles up through water,
collecting in the inverted gas jar by displacing water downward.