An electrostatic precipitator installed in a thermal power station removes which pollutant from the flue gas?
- A.Sulphur dioxide
- B.Oxides of nitrogen
- C.Particulate matter
- D.Carbon dioxide
Correct answer
Explanation
The correct answer is C, Particulate matter. An electrostatic precipitator gives the dust and ash particles in the flue gas an electric charge as they pass an electrode, and then collects them on plates carrying the opposite charge; the plates are shaken so that the collected ash falls into a hopper. It is the standard device for cleaning the chimney gases of a coal-fired power station and can remove the great majority of the particles. Options A and B are wrong because gases are not charged and collected this way; sulphur dioxide and the oxides of nitrogen are removed instead by a scrubber, in which the gas is washed with water or a lime slurry. Option D is wrong because carbon dioxide is not removed by either device in ordinary practice.
Read the full article: Air Pollution and Air Quality: Pollutants, AQI and Laws
Practice Questions
View allWhich of the following is a secondary air pollutant?
- A.Sulphur dioxide
- B.Carbon monoxide
- C.Peroxyacetyl nitrate
- D.Particulate matter
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A secondary pollutant is never emitted from a source; it is manufactured in the atmosphere itself when primary pollutants react with one another or with sunlight.
Read the full explanation →Which of the following is the chief component of photochemical smog?
- A.Sulphur dioxide
- B.Ozone
- C.Methane
- D.Carbon dioxide
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Photochemical smog, also called Los Angeles smog, forms in warm, dry, sunny weather when oxides of nitrogen from vehicle exhaust and unburnt hydrocarbons react under ultraviolet light.
Read the full explanation →Carbon monoxide is dangerous to human beings mainly because it:
- A.Combines with haemoglobin to form carboxyhaemoglobin
- B.Dissolves in water to form a strong acid
- C.Destroys the ozone layer of the stratosphere
- D.Settles in the alveoli as fine dust
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Carbon monoxide binds to the haemoglobin of the blood roughly two hundred times more readily than oxygen does, and the carboxyhaemoglobin so formed cannot carry oxygen.
Read the full explanation →Along with the oxides of nitrogen, which gas is chiefly responsible for acid rain?
- A.Carbon monoxide
- B.Methane
- C.Sulphur dioxide
- D.Argon
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Sulphur dioxide, released when coal and oil containing sulphur are burnt, is oxidised in the atmosphere to sulphur trioxide, which dissolves in water droplets to give sulphuric acid.
Read the full explanation →The damage to the marble of the Taj Mahal, popularly called 'marble cancer', is caused chiefly by:
- A.Carbon dioxide
- B.Sulphur dioxide
- C.Chlorofluorocarbons
- D.Ground-level ozone
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Sulphur dioxide from industry and traffic around Agra is oxidised in the air and comes down as sulphuric acid, which attacks the calcium carbonate of marble.
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