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41
Cooking gas is a mixture of
Discuss
Answer & Solution
Answer: Option C
Solution:
Liquefied petroleum gas (LPG), also called LP gas, any of several liquid mixtures of the volatile hydrocarbons propene, propane, butene, and butane.
42
Thermal electricity is generated by using which of these ?
Discuss
Answer & Solution
Answer: Option C
Solution:
Traditional thermal power plants: also called combustion power plants, they operate with energy produced by a steam boiler fueled by coal, natural gas, heating oil, as well as by biomass. The steam activates a turbine which, in turn, drives an alternator to produce electricity.
43
Which of the following is the major constituent of LPG?
Discuss
Answer & Solution
Answer: Option D
Solution:
Butanes are highly flammable, colourless, easily liquefied gases. When blended with propane and other hydrocarbons, it is referred to commercially as LPG, for liquefied petroleum gas.
44
Which variety of coal contains recognisable traces of the original plant material ?
Discuss
Answer & Solution
Answer: Option C
Solution:
Peat contains recognizable traces of the original plant material. Initially the peat is converted into lignite or ‘brown coal’ - these are coal-types with low organic maturity. In comparison to other coals, lignite is quite soft and its colour can range from dark black to various shades of brown.
45
Which of the following processes is used for the production of Biodiesel ?
Discuss
Answer & Solution
Answer: Option C
Solution:
Biodiesel production is the process of producing the biofuel, biodiesel, through the chemical reactions of transesterification and esterification. This involves vegetable or animal fats and oils being reacted with short-chain alcohols (typically methanol or ethanol).
46
The chief source of naphthalene is
Discuss
Answer & Solution
Answer: Option A
Solution:
Most naphthalene is derived from coal tar. From the 1960s until the 1990s, significant amounts of naphthalene were also produced from heavy petroleum fractions during petroleum refining, but today petroleum-derived naphthalene represents only a minor component of naphthalene production.
47
The gas that usually causes explosions in coal mines is
Discuss
Answer & Solution
Answer: Option D
Solution:
There are two main types of coalmine explosions: methane and coal dust. Methane explosions occur when a buildup of methane gas contacts a heat source and there is not enough air to dilute the gas level below its explosion point.
48
Submarines move under water. They have engines that run on
Discuss
Answer & Solution
Answer: Option B
Solution:
Early submarines used a direct mechanical connection between the engine and propeller, switching between diesel engines for surface running, and electric motors for submerged propulsion. Diesel electric submarines have a stealth advantage over their nuclear counterparts.
49
Which is the highest quality of hard coal?
Discuss
Answer & Solution
Answer: Option A
Solution:
Anthracite, often referred to as hard coal, is a hard, compact variety of coal that has a submetallic luster. It has the highest carbon content, the fewest impurities, and the highest energy density of all types of coal and is the highest ranking of coals.
50
The main source of Naphthalene is
Discuss
Answer & Solution
Answer: Option C
Solution:
Most naphthalene is derived from coal tar. From the 1960s until the 1990s, significant amounts of naphthalene were also produced from heavy petroleum fractions during petroleum refining, but today petroleum-derived naphthalene represents only a minor component of naphthalene production.