Please Please help

Dear Student
1.a) A good fuel is one that has a low ignition temperature so that it catches fire easily and a high calorific value so that lot of heat is generated.
2. b) Incomplete combustion of coal and hydrocarbon forms carbon monoxide.
        C_(s) + $\frac{1}{2}$O_2(g) $\stackrel{∆}{\to }$ CO_(g)           
3. d) Coal contains S as the trace element. When coal is burnt, sulphur also combines with oxygen to form sulphur dioxide (SO₂). SO₂ reacts with atmospheric water vapors in the atmosphere to cause acid rain.
4. c) Cutting off the supply of air is the most suitable method to extinguish a flame. Since air contains oxygen which is a supporter of combustion, covering fire with any substance which does not provide the supply of oxygen can extinguish a flame
5. a) The hottest zone is the non-luminous zone. This zone is blue-colored due to complete combustion.

Regards