Pollution Monitoring Instruments

Question 1

1. In West-Gaeke colourimetric procedure, the intensity of the red purple colour is measured photometically and it is proportional to the concentration of sulphur dioxide. What is the red purple coloured compound?
   a) Sodium tetra chloromercurate
   b) Dicholorosulphitomercurate complex
   c) Ammonia molybdate
   d) Paraosaniline sulphonic acid

Answer 1

d) Paraosaniline sulphonic acid

Question 2

2. The conductivitimetry method, involves bubbling
   sulphur dioxide through a solution containing sulphuric
   acid and which of the following?
   a) Water
   b) Hydrogen peroxide
   c) Iodine
   d) Formaldehyde

Answer 2

b) Hydrogen peroxide

Question 3

5. Which of the following is not true about using gas
   chromatography for measuring pollutants in the air?
   a) Pollutants react rapidly in the column
   b) Pollutants may not be detected by the detectors
   c) Special column and support materials are required
   d) Pollutants may elude rapidly from the column

Answer 3

d) Pollutants may elude rapidly from the column

Question 4

3. Which of the following are not the characteristics of
   conductivitimetry method used to measure sulphur
   dioxide?
   a) Fast response
   b) High sensitivity
   c) Free from interference by other gases
   d) Good accuracy

Answer 4

c) Free from interference by other gases

Question 5

6. The ability of sulphur dioxide to reduce iodine is used in
   which of the following methods?
   a) Colorimetry
   b) Conductivitimetry
   c) Coulometry
   d) Gas chromatography

Answer 5

c) Coulometry

Question 6

4. Which of the following are not the characteristics of
   colorimetry method used to monitor sulphur dioxide?
   a) It is simple
   b) It has high sensitivity
   c) It has good specificity
   d) It is affected by interference from H2SO4, SO3, NH3, etc

Answer 6

d) It is affected by interference from H2SO4, SO3, NH3, etc

Question 7

7. Which of the following materials are used as electrodes
   in the coulometric method for the measurement of
   sulphur dioxide?
   a) Gold
   b) Silver
   c) Platinum
   d) Nicke

Answer 7

c) Platinum

Question 7

8. Which of the following is the detection limit of the
   coulometric method used for measurement of sulphur
   dioxide?
   a) 0.1 ppm
   b) 1 ppm
   c) 2 ppm
   d) 0.01 ppm

Answer 7

d) 0.01 ppm

Question 8

9. Sensitivity to total sulphur by Flame-photometric
   detector is which of the following levels?
   a) 0.1 ppm
   b) 1 ppm
   c) 2 ppm
   d) 0.01 ppm

Answer 8

d) 0.01 ppm

Question 9

10. Which of the following methods are not used for the
    measurement of sulphur dioxide?
    a) Colorimetric method
    b) Correlation spectroscopy
    c) Paramagnetic analyzers
    d) Flame-photometry

Answer 9

c) Paramagnetic analyzers

Question 10

11. Which of the following is the wavelength of the
    radiation generated when an air stream containing sulphur
    dioxide is burned in a hydrogen-rich flame?
    a) 243 nm
    b) 394 nm
    c) 467 nm
    d) 516 nm

Answer 10

b) 394 nm

Question 11

13. In conductivitimetric method, the concentration of
    sulphur dioxide is proportional to which of the following
    parameters of the saw-tooth waveform?
    a) Average voltage
    b) Peak voltage
    c) Slope
    d) RMS voltage

Answer 11

c) Slope

Question 12

15. The response of coulometric method is instantaneous.
    a) True
    b) False

Answer 12

b) False

Question 12

14. In the conductivitimetric method, to measure the
    conductivity of the cell, 5V ___________ is applied across
    the electrodes.
    a) DC
    b) AC
    c) Pulsating DC
    d) DC or AC

Answer 12

b) AC

Question 13

1. In Saltzman method, which of the following are formed when air containing NO2 is passed in an absorbing solution consisting of the sulphanilic acid and diamine dissolved in
   the acetic acid medium?
   a) Blue colour dye complex
   b) Green colour dye complex
   c) Pink colour dye complex
   d) Orange colour dye complex

Answer 13

c) Pink colour dye complex

Question 14

2. NO can be analysed by converting it into NO2 and
   passing it through potassium permanganate. Which of the following is the main disadvantage of this method?
   a) Less accuracy
   b) Dye formed is unstable
   c) Dye formed is colourless
   d) Quantity of dye is low

Answer 14

b) Dye formed is unstable

Question 15

3. In Jacob-Hochheiser method, NO2 is passed through a
   dilute solution of sodium hydroxide forming the nitrite ion.
   The nitrite ion is reacted with sulphanilamide and ethylene
   diamine in which of the following to form the highly
   coloured azo dye?
   a) Sulphuric acid
   b) Hydrochloric acid
   c) Nitric acid
   d) Phosphoric acid

Answer 15

d) Phosphoric acid

Question 16

4. Which of the following methods results in the formation
   of yellow coloured compound?
   a) Griess-Saltzman method
   b) Phenoldisul phonoic acid method
   c) Chemiluminescence method
   d) West-Gaeke method

Answer 16

b) Phenoldisul phonoic acid method

Question 17

5. Which of the following is the most common application
   of Chemiluminescence method used for the analysis of
   Nitrogen oxides?
   a) In medical applications
   b) In automotive exhaust gases
   c) In manufacturing processes
   d) In chemical industries

Answer 17

b) In automotive exhaust gases

Question 18

6. Which of the following is the wavelength at which CO
   laser operates?
   a) 1.005 µm
   b) 5.307 µm
   c) 4.952 µm
   d) 6.179 µm

Answer 18

b) 5.307 µm

Question 19

7. CO laser is operated at liquid nitrogen temperature.
   a) True
   b) False

Answer 19

a) True

Question 19

8. The chemiluminescence reactor with ozonator is specific
   to which of the following compounds?
   a) N2
   b) NO
   c) NO2
   d) N2O

Answer 19

b) NO

Question 20

9. In which of the following ways can chemiluminescence occur in compounds of nitrogen?
   a) When NO2 returns to ground state from excited state
   b) When NO reacts with oxygen
   c) When NO reacts with ozone
   d) When NO2 is reduced to NO

Answer 20

a) When NO2 returns to ground state from excited state

Question 21

10. West-Gaeke colorimetric method is used to analyse
    oxides of nitrogen.
    a) True
    b) False

Answer 21

b) False

Question 22

3. Which of the following are not the characteristics of Non-dispersive infrared analyzer method? a) Easy to maintain b) High response speed c) Effect of interfering components is high d) High sensitivity

Answer 22

c) Effect of interfering components is high

Question 22

1. Which of the following is the full scale range of Infrared spectroscopy method used for measurement of carbon monoxide? a) 0-2 ppm b) 0-500 ppm c) 0-1 ppm d) 0-50 ppm

Answer 22

d) 0-50 ppm

Question 23

2. Which of the following is the full scale range of Gas chromatography method used for measurement of carbon monoxide? a) 0-200 ppm b) 0-500 ppm c) 0-1 ppm d) 0-50 ppm

Answer 23

a) 0-200 ppm

Question 24

4. Non-dispersive infrared analyzer depends on the characteristic absorption of the CO molecule at a wavelength of __________ a) 5.4 µm b) 4.6 µm c) 8.9 µm d) 10.8 µm

Answer 24

b) 4.6 µm

Question 25

5. The zero of the scale is calibrated using which of the following as the sample? a) Air b) Water c) Inert gas d) Pure nitrogen

Answer 25

d) Pure nitrogen

Question 26

6. The disadvantage of Non-dispersive infrared analyzer is that the effect of flow rate is large. a) True b) False

Answer 26

b) False

Question 27

7. A stripper column used in gas chromatography, can be used to retain which of the following when an air sample is passed through it? a) CO b) Methane c) Light hydrocarbons d) Heavy hydrocarbons

Answer 27

d) Heavy hydrocarbons

Question 28

8. Which of the following is not a component of the mixture present in the reference cell of Non-dispersive infrared analyzer? a) CO b) Nitrogen c) Water vapour d) Hydrogen

Answer 28

d) Hydrogen

Question 29

9. Hydrogen flame ionization detector can be used to detect only the peak of CO and not methane. a) True b) False

Answer 29

b) False

Question 30

10. CO analyzers based on infrared absorption would give greater sensitivity under which of the following conditions? a) With larger cell path lengths b) With smaller cell path lengths c) By changing the gases in the reference cell d) By increasing the sample flow rate

Answer 30

a) With larger cell path lengths

Question 31

2. Which of the following is the most abundant hydrocarbon which is emitted into the atmosphere by biological activity? a) Ethane b) Methane c) Poly Aromatic hydrocarbons d) Pentane

Answer 31

b) Methane

Question 31

1. Which of the following methods cannot be used for the estimation of hydrocarbons? a) Mass spectroscopy b) Chemiluminescence method c) Ultraviolet absorption d) Gas chromatography

Answer 31

b) Chemiluminescence method

Question 32

3. Flame ionization detectors are sensitive to which of the following gases? a) Carbon dioxide b) Methane c) Carbon monoxide d) Sulphur dioxide

Answer 32

b) Methane

Question 32

4. How can carbon monoxide be detected using flame ionization detectors while using gas chromatography technique? a) By converting it into carbon dioxide b) By converting it into methane c) By mixing it with combustible gases d) It cannot be detected

Answer 32

b) By converting it into methane

Question 33

5. Which of the following organic compounds will have the highest intensity of response when introduced in a flame ionization detector? a) Methane b) Ethane c) Propane d) Butane

Answer 33

d) Butane

Question 34

6. Propane would give three times the intensity of response as compared to methane. a) True b) False

Answer 34

a) True

Question 35

7. In flame ionization detectors, which of the following is the range adequate for atmospheric sampling? a) 0-1 ppm b) 0-2 ppm c) 0-20 ppm d) 0-100 ppm

Answer 35

c) 0-20 ppm

Question 36

8. Which of the following methods make use of pyrolysis while used for detecting methane? a) Mass spectroscopy b) Flame ionization detector c) Ultraviolet absorption d) Gas chromatography

Answer 36

b) Flame ionization detector

Question 37

9. In flame ionization detector, the ions collected on the negatively charged grid are amplified at the high impedance amplifier. a) True b) False

Answer 37

b) False

Question 38

10. Which of the following is not the characteristic of flame ionization detector? a) Good linearity b) Narrow range of concentration c) High sensitivity d) Fast response

Answer 38

b) Narrow range of concentration