Question

What is a good fuel?

Answer 1

A good or an ideal fuel are those which can be transported and packaged, which undergo complete combustion and leave no residues behind.

Answer 2

A good fuel is one:
(i) which has high calorific value
(ii) which has a proper ignition temperature
(iii) which burns out without giving out any smoke or harmful gases.
(iv) which burns smoothly and does not leave behind much ash after burning
(v) which is cheap, easily available, easy to handle, safe to transport and convenient to store.