Answer:
1. Heating coal reduces the mass by the loss of moisture.
2. Presence of moisture reduces the heating value of coal.
3. It is used to produce energy and it is easier for transportation.
4. Coal on refining is used to prepare phenol, naphthalene and other useful chemicals.
5. On combustion produces sufficient supply of energy, Hence it is used as a full time energy source.
6. Not too much of ash is produced on combustion.