Destructive distillation of mineral coal in laboratory :

Mineral coal is taken in a hard glass test tube. In a second test tube some water is taken. The apparatus is arranged as shown in the figure:

The coal is heated in a Bunsen burner and the gas coming out is passed through water in the other test tube. Sometimes later deposition of coal tar would be found in the test tube containing water. A gas will come out through the tube connected with the upper part of the test tube. This gas is called coal gas. Now the portion left out in the tube containing mineral coal is called coke.