Question

The layer containing petroleum oil and gas is:
A. below water
B. between water and sand
C. below sand
D. above the water

Answer 1

Hint:We know that petroleum is a flammable liquid. Petroleum is a mixture of different hydrocarbons and other organic compounds. It is converted to products, which are consumed by us, through refining. Some products are petrol, diesel etc.

Complete step by step answer:
Petroleum consists of crude oil and sometimes natural gas also. At a certain temperature and pressure, the basic hydrocarbons like methane, ethane, propane exist as gases.
Generally petroleum oil and natural gas are separated on the basis of its density. As we know that oil has less density than water, which is the reason for floating of oil above water. While gases have lower density than oil and water. Thus gases will float above oil which is floating above water. So we can say that the oil and gas floats above the water.
Thus the layer containing petroleum oil and gas is above the water.

Hence, the correct option is D.

Additional information:
Generally, the main source of petroleum oil and gas is rocks. Petroleum oil will move into a reservoir rock. One example of reservoir rock is sandstone. The reservoir rock has some pores in which the petroleum oil and gas is placed. Oil is trapped between the two impermeable layers.

Note:
The following table given below shows the difference in the density of water, oil and gas.

Type of compound	Density value
Oil	$0.93{{kg}}.{{{L}}^{ - 1}}$
Water	${{1kg}}.{{{L}}^{ - 1}}$
Gas	$0.7 - 0.9{{kg}}.{{{L}}^{ - 1}}$

Both petroleum oil and gas lie on the water. Therefore, water cannot be used to extinguish fire produced by petroleum. But when water is used in a fine mist, it can be used to extinguish fire.