Tick (√ ) the only correct choice among the following.

i. Which one of the following is less polluting fuel?

a. Natural gas b. coal

c. kerosene d. petrol

ii. The main constituent of coal is

a. Carbon. b. oxygen

c. air d. water

iii. Which one of the following material is used for making shoe polish?

a. Paraffin wax b. petrol.

c. diesel d. lubricating oil

(i) – (a) natural gas.

Reason: Natural gas combustion in efficient ways and enough supply of oxygen release very less harmful material as compared to petrol, coal or kerosene. The Sulphur, nitrogen and carbon oxides are released around 50 to 60 percent lesser than petrol and other sources.

(ii) - (a) carbon

reason: Coal is formed from the dead vegetation which lived many years ago. Since most of the nitrogen and water get decomposed or fixed in their cycles, coal contains mainly organic matter containing carbon.

(iii) - (a) paraffin wax.

Reason: Paraffin wax mixed with turpentine is used in shoe polish. It cleans the shoes and also strengthens the leather of shoes.