The calorific values of three fuels A, B and C are 33 KJ/g, 150 KJ/g, respectively. A is solid, B is liquid and C is a gas at room temperature. On combustion, both A and B produces carbon dioxide while C explodes forming steam. B and C leave no residue after combustion while A leaves behind some solid residue. Which one of the three fuels is the most ideal? Give two reasons to support your answer.

Calorific value and ignition temperature of fuel X are 75 kJ/g and 200C respectively. These values for fuel Y are 50 kJ/g and 750C respectively. On burning, the fuel Y produces only CO₂ while fuel X produces CO₂ and CO. Which of the two is a better fuel? Give two reasons to support your answer.

The calorific values of five fuels A, B, C, D and E are given below:

(A) 48 kJ/g

(B) 17 kJ/g

(C) 150 kJ/g

(D) 50 kJ/g

(E) 30kJ/g

Which of the fuels could be: (i) cooking gas (ii) alcohol (iii) wood (iv) hydrogen (v) kerosene ?

Arrange the following fuels in the order of decreasing calorific values (keeping the fuels with highest calorific value first):

Biogas, Kerosene, Wood, Petrol, Hydrogen gas, Methane

Arrange the following fuels in order of increasing calorific values (keeping the fuels with lowest calorific value first):

LPG, Coal, Alcohol, Dung cakes, Diesel

Most of the fuels contain carbon as one of the constituents. Name a fuel which has very high calorific value but does not contain carbon.