(A) Analyse the advantages of Natural Gas as a source of energy.

i. Natural Gas can be used as a domestic and industrial fuel.

ii. It is used as fuel in power sector to generate electricity.

iii. It is used for heating purpose in Industries.

iv. It is used as raw material in chemical, petrochemical and fertilizer industries, as transport fuel and as cooking fuel.

v. Natural gas is also emerging as a preferred transport fuel (CNG)

vi. It is used as cooking fuel (PNG) at homes.

(B) ‘Minerals generally occur in different rocks.’ Examine the statement.

i. In igneous and metamorphic rocks minerals may occur in the cracks, crevices, faults or joints. The smaller occurrences are called veins and the larger are called lodes.

ii. In sedimentary rocks a number of minerals occur in beds or layers.

iii. They have been formed as a result of deposition, accumulation and concentration in horizontal strata. Example are: Coal and some forms of iron ore.

iv. Certain minerals may occur as alluvial deposits in sands of valley floors.

v. Base of hills. These deposits are called ‘placer deposits.’ For example: Gold, silver, tin and platinum are most important among such minerals.

vi. Another mode of formation involves the decomposition of surface rocks, and the removal of soluble constituents, leaving a residual mass of weathered material containing ores. Bauxite is formed this way.