Question

why are gaseous fuel better than the solid and liquid ones

Answer 1

Gaseous fuels are best because gaseous fuel has high calorific value and no ash on burning i.e. 100% combustion takes place easily while in solid fuel calorific value is less and ash is remained after burning i.e. complete combustion take place with difficulty. And when it comes to liquids they let out a lot of smoke which isn't good for our environment.