Pollution Monitoring Instruments Pollution Monitoring Instruments Multiple Choice Questions and Answers

Pollution Monitoring Instruments Multiple Choice Questions and Answers

1. 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: 4.6 µm.

2. 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: AC.

3. 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: 0.01 ppm.

4. 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: Paraosaniline sulphonic acid.

5. 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: It is affected by interference from H2SO4, SO3, NH3, etc.

6. 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: Hydrogen peroxide.

7. 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: Free from interference by other gases.

8. 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: Pollutants may elude rapidly from the column.

9. 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) Nickel

Answer: Platinum.

10. 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: Coulometry.

11. 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: 0.01 ppm.

12. 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: Paramagnetic analyzers.

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: Slope.

14. 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: 394 nm.

15. 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: 5.307 µm.

16. 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: Pink colour dye complex.

17. The chemiluminescence reactor with ozonator is specific to which of the following compounds?

a) N2

b) NO

c) NO2

d) N2O

Answer: NO.

18. 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: Phenoldisul phonoic acid method.

19. 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: When NO2 returns to ground state from excited state.

20. 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: Dye formed is unstable.

21. 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: Phosphoric acid.

22. 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: In automotive exhaust gases.

23. 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: 0-50 ppm.

24. 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: Effect of interfering components is high.

25. 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: Pure nitrogen.

26. 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: With larger cell path lengths.

27. 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: Heavy hydrocarbons.

28. 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: Hydrogen.

29. 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: 0-200 ppm.

30. 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: Flame ionization detector.

31. 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: By converting it into methane.

32. 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: Chemiluminescence method.

33. 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: Narrow range of concentration

34. 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: Methane.

35. 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: Butane.

36. Flame ionization detectors are sensitive to which of the following gases?

a) Carbon dioxide

b) Methane

c) Carbon monoxide

d) Sulphur dioxide

Answer: Methane.

37. 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: 0-20 ppm.

38. In flame ionization detector, the ions collected on the negatively charged grid are amplified at the high impedance amplifier.

a) True

b) False

Answer: False.

39. Propane would give three times the intensity of response as compared to methane.

a) True

b) False

Answer: True.

40. Hydrogen flame ionization detector can be used to detect only the peak of CO and not methane.

a) True

b) False

Answer: False.

41. The disadvantage of Non-dispersive infrared analyzer is that the effect of flow rate is large.

a) True

b) False

Answer: False.

42. CO laser is operated at liquid nitrogen temperature.

a) True

b) False

Answer: True.

43. West-Gaeke colorimetric method is used to analyse oxides of nitrogen.

a) True

b) False

Answer: False

44. 5.307 µm is the wavelength at which CO laser operates?

a) True

b) False

Answer: True.

45. The response of coulometric method is instantaneous.

a) True

b) False

Answer: False.