Important Questions for Class 8 Chapter 5 - Coal and Petroleum

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Important questions based on NCERT syllabus for Chapter 5 - Coal and Petroleum:

Question-1: Explain the process of carbonisation.

Solution: About 300 million years ago the earth had dense forests in low lying wetland areas. Due to natural processes, like flooding, these forests got buried under the soil. As more soil got deposited over them, they were compressed. The temperature also rose as they sank deeper and deeper. Under high pressure and high temperature, dead plants got slowly converted to coal. As coal contains mainly carbon, the slow process of conversion of dead vegetation into coal is called carbonisation.

Question-2: How coal gas is obtained? Enlist its uses.

Solution: Coal gas is obtained during the processing of coal to get coke.
It is used as a fuel in many industries situated near the coal processing plants. Coal gas was used for street lighting. Now a days, it is used as a source of heat rather than light.

Question-3: Give the uses of natural gas.

Solution: Natural gas is used as a starting material for the manufacture of a number of chemicals and fertilisers.

Compressed Natural Gas (CNG) is used for power generation. It is now being used as a fuel for transport vehicles because it is less polluting and a cleaner fuel.

The great advantage of CNG is that it can be used directly for burning purposes in homes and factories where it can be supplied through pipes.