This set of Air Pollution Control Multiple Choice Questions & Answers (MCQs) focuses on “Analysis of Air Pollutants”.
1. How are air quality measurements generally done?
a) Continuous automatic analysers
b) Laboratory analysis
c) Depends on the analysis
d) Manual checking
View Answer
Explanation: Air quality is measured using automatic analysers. These instruments do continuous analyses. However, it is important to note that laboratory analysis is carried out occasionally for spot-checking of samples.
2. When are conventional methods used when analysing air quality?
a) Every sample is checked by hand
b) For spot checking
c) When failure is detected
d) When there is no alternative
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Explanation: Usually, air quality measurement samples are checked by automatic methods. From time to time, the examination of samples by conventional methods ensures accurate readings, i.e., spot-checking is done for discrete samples.
3. On what basis is the analysis of gaseous pollutants classified?
a) Biological and chemical measurement
b) Physical and biological measurement
c) Physical and chemical measurement
d) Wet and dry measurement
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Explanation: The analysis of gaseous pollutants is based on chemical and physical measurements. The studies vary based on the method. One involves the examination of the product of a chemical reaction, while the other tests the physical property of the pollutant itself.
4. Which of the following is not a method commonly used to manually measure atmospheric sulphur dioxide?
a) Colourimetry
b) Iodometry
c) Turbidimetry
d) Conductometry
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Explanation: Except for the conductometry method, all the listed procedures are used to detect ambient sulphur dioxide. These processes all involve chemical reactions. The detection and intensity of the product indicate the presence and concentration of sulphur dioxide.
5. How do iron and other heavy metals interfere in the sampling of sulphur dioxide?
a) Detected concentration of sulphur dioxide is lower
b) Detected concentration of sulphur dioxide is higher
c) They hinder the chemical reaction
d) They do not interfere
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Explanation: Iron and other heavy metals interfere in the manual measurement of ambient sulphur dioxide. These metal salts react with sulphur dioxide, which shows a lower reading of the pollutant. EDTA is added to the reaction mixture to avoid this.
6. Other than heavy metals, which of the following materials hinders the sampling of sulphur dioxide?
a) Carbon monoxide
b) Nitrogen dioxide
c) Nitric oxide
d) Carbon dioxide
View Answer
Explanation: Nitrogen dioxide hinders the accurate detection of ambient sulphur dioxide. Nitrogen dioxide will participate in the chemical reaction, skewing the final readings. Sulphamic acid is added to avoid this impedance.
7. Which of the following methods is not used for the automatic detection of ambient sulphur dioxide?
a) Colourimetry
b) Conductometry
c) Photometry
d) Flame photometry
View Answer
Explanation: Of the given options, only photometry is not used for the detection of ambient sulphur dioxide. In the conductometry method, the electrical conductivity of the reaction product is analysed.
8. Which of the following methods is used to detect the concentration of sulphur dioxide from the stack?
a) Colourimetric
b) Turbidimetric
c) Conductometric
d) Electrochemical method
View Answer
Explanation: The electrochemical method is a direct method of detection of sulphur dioxide from stack emissions. In this method, sulphur dioxide diffuses through a semipermeable membrane and gets absorbed at the electrode.
9. Other than the electrochemical method, which other methods are used to detect sulphur dioxide from stack emissions?
a) IR and UV spectrophotometry
b) Mass spectroscopy
c) HPLC
d) UV spectrometry only
View Answer
Explanation: Both UV and IR spectrophotometry can be used for detection. This kind of sampling is based on the wavelengths of light sulphur dioxide absorbs. The absorption is proportional to the concentration of sulphur dioxide.
10. Which method is preferred for the analysis of sulphur dioxide from stack emissions?
a) Spectrophotometry
b) Electrochemical method
c) Colourimetry
d) Conductometry
View Answer
Explanation: The electrochemical method is preferred for sulphur dioxide analysis. This method is portable and simple compared to the spectrophotometry one; it is also specific to sulphur dioxide detection.
Sanfoundry Global Education & Learning Series – Air Pollution Control.
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