a – iii

Bitumen is a petroleum product used for surfacing of roads.

b – iv

Natural gas when compressed under high pressure, it is called CNG.

c – i

Petroleum is called black gold because when it is extracted from earth’s surface it is black in colour and on refining we obtain many useful products which have high commercial values.

d – ii

Paraffin wax is obtained from the refining of petroleum and is used for making candles, vaselines, ointments etc.