Dear Student ,
Many coal derivatives are produced indirectly by the destructive distillations of coal. The destructive distillations process takes place in the absence of oxygen (within an airtight oven) that prevents the coal from burning. The remaining material, coke, is nearly pure carbon.
We get many useful products like coke, coal tar and coal gas etc.
1.Coke -Its an solid residue left after the destructive distillations of coal.
2.Coal tar- Its an thick black liqiud which is mixture of many carbon compounds.
3.Ammonical liquor- Ammonia produced in the process is absorbed in water to form ammonium hydroxide solution called as ammonical liquor.
4.Coal gas- Gaseous component mixture of hydrogen,methane and carbon monooxide.