Strong heating of coal in the absence of air or oxygen is called destructive distillation.
Coal (Fossil Fuel):
Coal is an important solid fossil fuel.
Destructive distillation of coal provides useful by-products.
The fundamental by-products are:
• coal tar
• ammoniacal alcohol
• coal gas
Destructive Distillation of Coal Experiment:
Let’s understand the concept of destructive distillation through experiment in the laboratory.
Required Material :
The materials needed for the experiment of destructive distillation are as follow:
- Two hard-boiling glass test tubes marked as A and B
- 2 delivery tubes
- clamp stand
- rubber stoppers
- powdered coal
- Take little powdered coal in test tube A.
- Test tube A is fitted with a rubber stopper carrying a delivery tube and is clamped to the stand.
- Test tube B containing water is clamped vertically to the stand.
- The burner is lighted and the test tube A is heated first gently and then intensely.
- The gas liberated by heated coal pass through the water in test tube B.
- You will notice dark coal tar settled down at the lower part of test tube B.
- The ammoniacal compounds formed will dissolve in water in test tube B to form ammoniacal liquor.
- Coal gas insoluble in water escapes through the side delivery tube. It can be lighted at the end of the open tube. It is a mixture of hydrogen, methane, carbon monoxide and other gases.
- Solid hard black residue left behind in test tube A is coke. It is an almost pure form of carbon.