Acid rain is mainly caused by the atmospheric release of which gases?
- A.Carbon dioxide and methane
- B.Sulphur dioxide and oxides of nitrogen
- C.Carbon monoxide and ozone
- D.Chlorofluorocarbons and halons
Correct answer
Explanation
The correct answer is B, sulphur dioxide and oxides of nitrogen. These gases come from burning coal and oil in thermal power stations, smelters and vehicles, are oxidised in the atmosphere and dissolve in water droplets to form sulphuric acid and nitric acid, which come down as acid rain. Option A is wrong because carbon dioxide and methane are greenhouse gases; carbon dioxide does dissolve to form weak carbonic acid, but that only makes normal rain slightly acidic at a pH near 5.6 and is not what is meant by acid rain. Option C is wrong because carbon monoxide is a poisonous gas that does not form a strong acid, and ozone at ground level is an irritant in smog rather than a source of acidity. Option D is wrong because chlorofluorocarbons and halons destroy stratospheric ozone and are the concern of the Montreal Protocol, a separate problem from acid rain.
Read the full article: Ozone Layer and Acid Rain: Causes, Effects, Treaties
Practice Questions
View allWhich of the following statements about ozone is true?
- A.All of the options
- B.Ozone is highly reactive
- C.Ozone protects us from the harmful UV radiation of the sun
- D.Ozone is the major constituent of photochemical smog
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Each of the other three statements is correct on its own, which is exactly why the combined option is the answer.
Read the full explanation →Which of the following is a secondary pollutant?
- A.Carbon monoxide
- B.Smog
- C.Carbon dioxide
- D.Fly ash
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A primary pollutant is released directly from a source, while a secondary pollutant is formed in the atmosphere when primary pollutants react.
Read the full explanation →Which one of the following is NOT a greenhouse gas found naturally in the atmosphere?
- A.Nitrogen oxide
- B.Carbon dioxide
- C.Methane
- D.Ozone
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Nitric oxide and nitrogen dioxide, together written as nitrogen oxides, are air pollutants that come mainly from combustion in vehicles and power stations; they help form smog and acid rain but are not counted among the greenhouse gases of the natural atmosphere.
Read the full explanation →The ozone layer that protects the earth from ultraviolet radiation lies in which layer of the atmosphere?
- A.Troposphere
- B.Stratosphere
- C.Mesosphere
- D.Thermosphere
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About nine tenths of the atmosphere's ozone lies in the stratosphere, roughly fifteen to thirty five kilometres above the surface, where ultraviolet rays split oxygen molecules and the free atoms combine with other oxygen molecules to make ozone.
Read the full explanation →The thickness of the ozone column in the atmosphere is measured in which unit?
- A.Dobson unit
- B.Curie
- C.Decibel
- D.Angstrom
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The Dobson unit, named after the scientist who built the instrument for measuring atmospheric ozone, expresses how thick the ozone column would be if all of it were brought down to the surface at standard temperature and pressure; a hundred Dobson units correspond to a layer one millimetre thick.
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