This set of Pollution Control Multiple Choice Questions & Answers (MCQs) focuses on “Effects of Air Pollutants on Materials”.
1. Which of the following particulates do not discolour fabrics?
a) Mist
b) Fumes
c) Dust
d) Soot
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Explanation: All the listed options (fumes, dust, soot), except for mist, discolour fabrics. Not only fabrics but particulates are also able to discolour painted surfaces and buildings. They form a particulate layer, which ruins the original colour.
2. Which of the following surfaces are affected by particulates like fumes?
a) Trees
b) Painted surfaces
c) Metal surfaces
d) Soil
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Explanation: Particulates like soot, fumes and dust can discolour painted surfaces when they are deposited on them. Other surfaces that can exhibit similar effects are fabrics and painted structures like buildings.
3. Which of the following properties of particulates is responsible for damaging surfaces?
a) Adhesive nature
b) Repulsive nature
c) Abrasive nature
d) Cohesive nature
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Explanation: Particulates damage surfaces because of their abrasive nature, especially when their impact velocity is high. Upon impact, their adhesive nature makes surfaces they impact less aesthetically pleasing.
4. Particulates corrode the surface of metals in the presence of which of the following substances?
a) Carbon dioxide and moisture
b) Oxygen and moisture
c) Carbon dioxide and moisture
d) Sulphur dioxide and moisture
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Explanation: Particulates, either by themselves or in the presence of sulphur dioxide and moisture, corrode the surface of metals (both ferrous and non-ferrous). Metals they can affect are steel, copper, and zinc, among others.
5. Which air pollutant is responsible for the most corrosion?
a) Sulphur dioxide
b) Nitrogen dioxide
c) Particulates
d) Carbon monoxide
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Explanation: Most of the given options corrode metals in some capacity. Particulates can do so by themselves, or with the help of sulphur dioxide. Though, the pollutant that causes the most corrosion amongst the given options is sulphur dioxide. It happens at low concentrations.
6. How high does the concentration of sulphur dioxide has to be to corrode steel?
a) 5 microgram per cubic meter
b) 50 microgram per cubic meter
c) 150 microgram per cubic meter
d) 500 microgram per cubic meter
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Explanation: The concentration at which sulphur dioxide starts corroding steel is very low. The concentration can be as low as about 50 micrograms per cubic meter, which is approximately 2 * 10-2 ppm.
7. At low concentrations, sulphur dioxide affects which of the following materials?
a) Metals
b) Rubber
c) Paint
d) Plastic
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Explanation: Even at low concentrations of about 1 ppm, sulphur dioxide can affect surfaces of various materials. Such materials are leather, paints and fabrics. Prolonged exposure can cause disintegration.
8. Which of the following materials absorbs sulphur dioxide, which causes its disintegration?
a) Steel
b) Cotton
c) Plastic
d) Leather
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Explanation: Leather is one such material which disintegrates upon absorption of sulphur dioxide. Steel gets corroded by sulphur dioxide, and fabrics can also be discoloured. These effects are because of its acidic nature.
9. Which material becomes brittle by exposure to sulphur dioxide?
a) Paper
b) Paint
c) Cotton
d) Leather
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Explanation: Paper becomes brittle and fragile upon prolonged exposure to sulphur dioxide. It can also get discoloured because of exposure to sulphur dioxide; fabrics and paints can also get discoloured. Leather disintegrates upon contact.
10. The phenomenon of weathering is attributed to which pollutant?
a) Methane
b) Ozone
c) Terpenes
d) Hydrogen sulphide
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Explanation: Ozone causes degradation of materials because it is highly reactive. Due to this property, it degrades materials like fabrics and rubbers upon prolonged exposure. The degradation of materials over long periods is termed as weathering.
11. Which of the following statements is false?
a) Ozone cracks synthetic rubber
b) Ozone affects rubbers at low concentrations
c) Ozone affects rubbers at high concentrations
d) Ozone does not affect fabrics
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Explanation: Synthetic rubber cracks upon exposure to ozone. This is because ozone is a strong oxidant. The cracking of synthetic rubber occurs at low concentrations of exposure to ozone, even as low as 10-2 ppm.
12. In ascending order, which materials does ozone affect?
a) Polyester < Cotton < Acetates < Nylons
b) Nylons < Polyester < Cotton < Acetates
c) Acetates < Nylons < Polyester < Cotton
d) Cotton < Acetates < Nylons < Polyester
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Explanation: Ozone is a strong oxidising agent and can affect fabrics. It is responsible for fading the fibres. The material it affects the most is polyester, and the material it affects the least is cotton. The answer is Cotton < Acetates < Nylons < Polyester.
13. Other than ozone, which oxidising agent affects fabrics?
a) Nitrogen dioxide
b) Sulphur dioxide
c) Ozone
d) Particulates
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Explanation: Ozone and nitrogen dioxide are oxidising agents that cause the fading of fabrics. Nitrogen dioxide, in particular, fades synthetic fabrics like acetate, nylon, and rayon. Nitrogen dioxide is not a particulate.
14. At what concentration and exposure levels does nitrogen dioxide affect fabric materials?
a) Low concentration and long periods
b) Low concentration and a short period
c) High concentration and a short period
d) High concentration and long periods
View Answer
Explanation: Even at low concentrations and long periods, nitrogen dioxide can cause fading of fabric materials. The concentrations are as low as 1 ppm, and the exposure period can be as short as 2 months.
15. Which pollutant causes damage to nickel-brass alloys?
a) Nitrogen dioxide
b) Ozone
c) Nitrates
d) Carbon monoxide
View Answer
Explanation: Particulates like nitrates can cause damage to the surface of nickel-brass alloys. This deterioration happens due to the process of corrosion, which occurs in the presence of moisture as well as air.
Sanfoundry Global Education & Learning Series – Pollution Control.
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