45 + Interview Questions in Pollution Monitoring Instruments in Analytical Instrumentation Page 1 InterviewSolution

1.	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 columnI had been asked this question during an online exam.I'd like to ask this question from Sulphur Di-oxide Monitoring topic in chapter Pollution Monitoring Instruments of Analytical Instrumentation
Answer» The CORRECT answer is (d) Pollutants may elude RAPIDLY from the column The best explanation: Most of the pollutants are extreme reactive MATERIALS. Hence, they may not pass through the column and appear at the detector.

Discussion

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 lowI had been asked this question in a national level competition.This key question is from Estimation of Nitrogen Oxides in chapter Pollution Monitoring Instruments of Analytical Instrumentation
Answer» The correct option is (b) Dye formed is unstable To EXPLAIN: NO can be analysed by converting it into NO2 and passing it through potassium permanganate. The MAIN disadvantage of this method is that the dye formed is unstable. HENCE, it is not suitable for a collection of 24 hours SAMPLE.

Discussion

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 ppmI got this question in semester exam.My doubt is from Sulphur Di-oxide Monitoring in chapter Pollution Monitoring Instruments of Analytical Instrumentation
Answer» The CORRECT choice is (d) 0.01 ppm Easiest explanation: Sensitivity to total SULPHUR by FLAME-photometric detector is 0.01 ppm. Here, SAMPLE air is introduced into a hydrogen-rich air flame.

Discussion

4.	Given below, is the diagram of Ultraviolet Fluorescence method. Identify the unmarked component.(a) Filter(b) Electronic circuit(c) Supply(d) Fluorescence chamberI got this question in an international level competition.I'm obligated to ask this question of Sulphur Di-oxide Monitoring topic in portion Pollution Monitoring Instruments of Analytical Instrumentation
Answer» Correct OPTION is (d) Fluorescence CHAMBER Easy explanation: The unmarked block is Fluorescence chamber. Here, fluorescence of SO2 is EMITTED.

Discussion

5.	Flame ionization detectors are sensitive to which of the following gases?(a) Carbon dioxide(b) Methane(c) Carbon monoxide(d) Sulphur dioxideThe question was posed to me in final exam.This interesting question is from Estimation of Hydrocarbons in division Pollution Monitoring Instruments of Analytical Instrumentation
Answer» Correct option is (B) METHANE The explanation is: Flame IONIZATION detectors are sensitive to methane since they are sensitive to organic compounds. They are insensitive to non-combustible gases. HENCE, they are not sensitive to carbon monoxide, carbon DIOXIDE and sulphur dioxide.

Discussion

6.	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 responseThe question was asked during an interview for a job.Origin of the question is Estimation of Hydrocarbons in chapter Pollution Monitoring Instruments of Analytical Instrumentation
Answer» RIGHT choice is (B) Narrow RANGE of CONCENTRATION For explanation: Narrow range of concentration is not the characteristic of flame ionization detector. It has a BROAD range of concentration.

Discussion

7.	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 acidThis question was addressed to me during a job interview.My doubt stems from Sulphur Di-oxide Monitoring in division Pollution Monitoring Instruments of Analytical Instrumentation
Answer» Right option is (d) Paraosaniline sulphonic ACID Easiest explanation: Sulphur dioxide reacts with SODIUM TETRA chloromercurate to FORM Dicholorosulphitomercurate complex which then reacts with formaldehyde and pararosaniline to form Parapsaniline sulphonic acid which is red purple COLOURED.

Discussion

8.	The zero of the scale is calibrated using which of the following as the sample?(a) Air(b) Water(c) Inert gas(d) Pure nitrogenI got this question by my school principal while I was bunking the class.The above asked question is from Estimation of Carbon Monoxide in section Pollution Monitoring Instruments of Analytical Instrumentation
Answer» Correct answer is (d) Pure NITROGEN Best explanation: The ZERO of the SCALE is calibrated using pure nitrogen as the sample. Optical FILTERS are used to minimize the effects of INTERFERING gases.

Discussion

9.	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) FormaldehydeThis question was addressed to me in exam.Question is taken from Sulphur Di-oxide Monitoring topic in portion Pollution Monitoring Instruments of Analytical Instrumentation
Answer» Right choice is (b) Hydrogen peroxide For EXPLANATION I would SAY: The conductivitimetry method, involves bubbling sulphur dioxide through a solution containing SULPHURIC acid and hydrogen peroxide. It RESULTS in the FORMATION of sulphuric acid.

Discussion

10.	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 µmI got this question during an internship interview.My doubt is from Estimation of Carbon Monoxide topic in division Pollution Monitoring Instruments of Analytical Instrumentation
Answer» The correct choice is (b) 4.6 µm The explanation is: Non-dispersive INFRARED analyzer depends on the characteristic ABSORPTION of the CO MOLECULE at a WAVELENGTH of 4.6 µm.

Discussion

11.	Hydrogen flame ionization detector can be used to detect only the peak of CO and not methane.(a) True(b) FalseI have been asked this question during an interview.This interesting question is from Estimation of Carbon Monoxide in section Pollution Monitoring Instruments of Analytical Instrumentation
Answer» Right choice is (b) False The BEST explanation: Hydrogen flame IONIZATION DETECTOR can be used to DETECT the peak of both CO and methane. The ACCURACY is about 2%.

Discussion

12.	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 voltageI have been asked this question by my school principal while I was bunking the class.This interesting question is from Sulphur Di-oxide Monitoring in section Pollution Monitoring Instruments of Analytical Instrumentation
Answer» CORRECT choice is (c) SLOPE Best explanation: In conductivitimetric METHOD, the concentration of SULPHUR dioxide is proportional to slope of the saw-tooth waveform. Current is recorded EVERY 15 minutes.

Discussion

13.	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) NickelThe question was posed to me in homework.The query is from Sulphur Di-oxide Monitoring topic in section Pollution Monitoring Instruments of Analytical Instrumentation
Answer» RIGHT answer is (c) Platinum To explain: In Coulometric arrangement, the ELECTRODES are made of platinum. These act as the ANODE and the CATHODE.

Discussion

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 nmI have been asked this question by my school principal while I was bunking the class.Origin of the question is Sulphur Di-oxide Monitoring topic in division Pollution Monitoring Instruments of Analytical Instrumentation
Answer» Right option is (B) 394 nm The EXPLANATION is: The wavelength of the radiation generated when an air stream containing sulphur dioxide is burned in a hydrogen-rich flame is 394 MM. A narrow band interference filter is USED to shield radiations with all other WAVELENGTHS.

Discussion

15.	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 rateThe question was asked in an online quiz.My question is based upon Estimation of Carbon Monoxide topic in portion Pollution Monitoring Instruments of Analytical Instrumentation
Answer» Correct answer is (a) With larger cell path LENGTHS The best explanation: CO analyzers based on infrared absorption would give GREATER sensitivity with larger cell path lengths. If 1m path LENGTH is given, the RANGE is from 0 to 50ppm.

Discussion

16.	Propane would give three times the intensity of response as compared to methane.(a) True(b) FalseI have been asked this question during an interview for a job.This question is from Estimation of Hydrocarbons topic in section Pollution Monitoring Instruments of Analytical Instrumentation
Answer» Right choice is (a) True Easiest explanation: Propane WOULD give three times the INTENSITY of response as compared to methane. This is because the intensity of response will be in PROPORTION with the number of CARBON atoms in the CHAIN.

Discussion

17.	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 ppmThis question was posed to me by my school teacher while I was bunking the class.I'm obligated to ask this question of Estimation of Carbon Monoxide in division Pollution Monitoring Instruments of Analytical Instrumentation
Answer» Right CHOICE is (a) 0-200 ppm To explain I would say: The full scale range of GAS chromatography method used for MEASUREMENT of carbon monoxide is 0-200 ppm. The DETECTOR used in this method is a flame ionization detector.

Discussion

18.	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) HydrogenI got this question during an online exam.This key question is from Estimation of Carbon Monoxide in division Pollution Monitoring Instruments of Analytical Instrumentation
Answer» The CORRECT OPTION is (d) Hydrogen Easy explanation: The reference cell CONTAINS a fixed quantity of gases. It contains CO, nitrogen and water VAPOUR.

Discussion

19.	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 complexI have been asked this question during an interview.I want to ask this question from Estimation of Nitrogen Oxides in section Pollution Monitoring Instruments of Analytical Instrumentation
Answer» The correct answer is (c) Pink colour dye complex Best explanation: In Saltzman method, a pink colour dye is formed when air CONTAINING NO2 is passed in an ABSORBING solution consisting of the sulphanilic acid and diamine dissolved in the acetic acid MEDIUM. It is SENSITIVE in the ppm range.

Discussion

20.	The response of coulometric method is instantaneous.(a) True(b) FalseI have been asked this question in an online interview.My question is taken from Sulphur Di-oxide Monitoring topic in section Pollution Monitoring Instruments of Analytical Instrumentation
Answer» Correct CHOICE is (B) False The best EXPLANATION: The response of coulometric method is not instantaneous. It may take about 4 minutes for 90 percent of the SIGNAL to appear for any CONCENTRATION of SO2.

Discussion

21.	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 detectedThis question was addressed to me by my school teacher while I was bunking the class.Enquiry is from Estimation of Hydrocarbons in section Pollution Monitoring Instruments of Analytical Instrumentation
Answer» Correct answer is (B) By converting it into methane Best explanation: Carbon monoxide cannot be detected directly USING flame IONIZATION detectors while using gas chromatography technique. Hence, it is CONVERTED into methane and is then detected.

Discussion

22.	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 methodThis question was posed to me in exam.Asked question is from Estimation of Nitrogen Oxides in section Pollution Monitoring Instruments of Analytical Instrumentation
Answer» The correct option is (b) Phenoldisul phonoic acid method For EXPLANATION I would SAY: Phenoldisul phonoic acid method results in the formation of YELLOW COLOURED compound. The intensity of the colour is measured to DETERMINE the concentration of NOx.

Discussion

23.	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 ACThis question was posed to me during an online exam.I'd like to ask this question from Sulphur Di-oxide Monitoring in portion Pollution Monitoring Instruments of Analytical Instrumentation
Answer» The correct choice is (B) AC Explanation: In the conductivitimetric METHOD, to measure the conductivity of the cell, 5V ALTERNATING current is APPLIED across the electrodes. This is because alternating current avoids polarisation.

Discussion

24.	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 industriesI had been asked this question in an interview for job.I'm obligated to ask this question of Estimation of Nitrogen Oxides topic in section Pollution Monitoring Instruments of Analytical Instrumentation
Answer» The correct choice is (b) In automotive exhaust gases Best explanation: The most common APPLICATION of Chemiluminescence method USED for the analysis of Nitrogen oxides is to measure the amount of NO in automotive exhaust gases. Chemiluminescence OCCURS DUE to the formation of new chemical bonds.

Discussion

25.	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 ppmThe question was posed to me in an international level competition.My question comes from Sulphur Di-oxide Monitoring in section Pollution Monitoring Instruments of Analytical Instrumentation
Answer» Right OPTION is (d) 0.01 ppm To explain I would say: The detection LIMIT of the coulometric method is 0.01 ppm. The shift in ANODE cathode potential is DETECTED by a THIRD electrode.

Discussion

26.	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 µmThis question was posed to me by my college director while I was bunking the class.My enquiry is from Estimation of Nitrogen Oxides topic in portion Pollution Monitoring Instruments of Analytical Instrumentation
Answer» The CORRECT answer is (b) 5.307 µm Explanation: CO LASER OPERATES at a WAVELENGTH of 5.307 µm. It is a DC-excited CONTINUOUS working laser.

Discussion

27.	The disadvantage of Non-dispersive infrared analyzer is that the effect of flow rate is large.(a) True(b) FalseI had been asked this question during an online interview.This is a very interesting question from Estimation of Carbon Monoxide topic in division Pollution Monitoring Instruments of Analytical Instrumentation
Answer» The correct choice is (b) False Easy explanation: In Non-dispersive infrared ANALYZER, the EFFECT of FLOW rate is small. Optical filters are used to MINIMIZE the effects of interfering gases.

Discussion

28.	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 chromatographyI got this question by my college director while I was bunking the class.My question comes from Estimation of Hydrocarbons topic in section Pollution Monitoring Instruments of Analytical Instrumentation
Answer» The CORRECT answer is (b) Flame ionization detector Explanation: Flame ionization detector makes USE of PYROLYSIS while used for detecting methane. It is used to detect ORGANIC compounds.

Discussion

29.	CO laser is operated at liquid nitrogen temperature.(a) True(b) FalseI have been asked this question in homework.I want to ask this question from Estimation of Nitrogen Oxides topic in portion Pollution Monitoring Instruments of Analytical Instrumentation
Answer» RIGHT choice is (a) True For explanation: CO LASER is OPERATED at liquid nitrogen TEMPERATURE. It is a DC-excited continuous working laser.

Discussion

30.	The chemiluminescence reactor with ozonator is specific to which of the following compounds?(a) N2(b) NO(c) NO2(d) N2OThis question was addressed to me in an online interview.This interesting question is from Estimation of Nitrogen Oxides topic in chapter Pollution Monitoring Instruments of Analytical Instrumentation
Answer» CORRECT OPTION is (b) NO To explain I would SAY: The chemiluminescence REACTOR with ozonator is specific to NO. Here, the SAMPLE containing NO is converted into NO2 by the ozonator.

Discussion

31.	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 NOThis question was posed to me by my college director while I was bunking the class.This key question is from Estimation of Nitrogen Oxides topic in chapter Pollution Monitoring Instruments of Analytical Instrumentation
Answer» The correct OPTION is (a) When NO2 returns to ground state from excited state Explanation: When NO2 returns to ground state from excited state, chemiluminescence occurs. NO2 in excited state returns to ground state with the EMISSION of RADIANT ENERGY.

Discussion

32.	West-Gaeke colorimetric method is used to analyse oxides of nitrogen.(a) True(b) FalseThis question was posed to me during an online exam.The doubt is from Estimation of Nitrogen Oxides in portion Pollution Monitoring Instruments of Analytical Instrumentation
Answer» Correct OPTION is (b) False Explanation: West-Gaeke colorimetric METHOD is not used to ANALYSE oxides of nitrogen. It is used to analyse sulphur DIOXIDE.

Discussion

33.	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 hydrocarbonsI got this question during an interview.This interesting question is from Estimation of Carbon Monoxide in section Pollution Monitoring Instruments of Analytical Instrumentation
Answer» The correct answer is (d) Heavy HYDROCARBONS To EXPLAIN I would say: A STRIPPER column can be USED to retain heavy hydrocarbons when an air sample is passed through it. It passes CO and methane into the column.

Discussion

34.	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 sensitivityI got this question in homework.The doubt is from Estimation of Carbon Monoxide topic in chapter Pollution Monitoring Instruments of Analytical Instrumentation
Answer» The CORRECT CHOICE is (c) Effect of interfering components is high To EXPLAIN I would say: Effect of interfering components is small for Non-dispersive infrared analyzer method. It depends on the characteristic absorption of the CO MOLECULE at a particular wavelength.

Discussion

35.	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, etcI had been asked this question during an interview.My enquiry is from Sulphur Di-oxide Monitoring in section Pollution Monitoring Instruments of Analytical Instrumentation
Answer» CORRECT answer is (d) It is AFFECTED by interference from H2SO4, SO3, NH3, etc Explanation: COLORIMETRY method is free from by the interference due to other gases such as It is affected by interference from H2SO4, SO3, NH3, etc. COLOUR intensity is sensitive to temperature.

Discussion

36.	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) ButaneI had been asked this question in an interview for job.My doubt is from Estimation of Hydrocarbons topic in section Pollution Monitoring Instruments of Analytical Instrumentation
Answer» Correct choice is (d) Butane Best EXPLANATION: Butane will have the HIGHEST intensity of response when introduced in a flame ionization detector. This is because the intensity of response will be in PROPORTION with the number of CARBON ATOMS in the chain.

Discussion

37.	The ability of sulphur dioxide to reduce iodine is used in which of the following methods?(a) Colorimetry(b) Conductivitimetry(c) Coulometry(d) Gas chromatographyI had been asked this question in my homework.My question is based upon Sulphur Di-oxide Monitoring topic in chapter Pollution Monitoring Instruments of Analytical Instrumentation
Answer» The correct option is (c) Coulometry The explanation: The ability of sulphur dioxide to REDUCE IODINE is used in Coulometry method to measure sulphur dioxide. The mass of I2 reacted PER unit TIME will indicate the amount of sulphur dioxide.

Discussion

38.	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 accuracyThe question was posed to me during an online interview.Asked question is from Sulphur Di-oxide Monitoring topic in portion Pollution Monitoring Instruments of Analytical Instrumentation
Answer» The correct option is (c) FREE from INTERFERENCE by other gases To elaborate: Conductivitimetry INSTRUMENTS are AFFECTED by other gases and they cause interference. The other gases may produce or remove IONS in the solution.

Discussion

39.	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 ppmI had been asked this question during an interview for a job.This question is from Estimation of Carbon Monoxide topic in portion Pollution Monitoring Instruments of Analytical Instrumentation
Answer» Correct choice is (d) 0-50 PPM For EXPLANATION I would say: The full scale range of Infrared spectroscopy method used for measurement of carbon monoxide is 0-50 ppm. It depends on the characteristic ABSORPTION of the CO MOLECULE at a particular WAVELENGTH.

Discussion

40.	Which of the following methods cannot be used for the estimation of hydrocarbons?(a) Mass spectroscopy(b) Chemiluminescence method(c) Ultraviolet absorption(d) Gas chromatographyI had been asked this question in an interview for job.Origin of the question is Estimation of Hydrocarbons topic in portion Pollution Monitoring Instruments of Analytical Instrumentation
Answer» RIGHT CHOICE is (b) Chemiluminescence method To explain I would say: Chemiluminescence method cannot be used for the ESTIMATION of HYDROCARBONS. This is because hydrocarbons do not produce chemiluminescence EFFECT.

Discussion

41.	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) PentaneThe question was asked during an interview.My query is from Estimation of Hydrocarbons in portion Pollution Monitoring Instruments of Analytical Instrumentation
Answer» Right option is (B) Methane The EXPLANATION: The most abundant hydrocarbon which is emitted into the atmosphere by BIOLOGICAL activity is methane. It is ALSO emitted by automobile exhausts, burning of coal, etc.

Discussion

42.	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 ppmThis question was posed to me in examination.My question is from Estimation of Hydrocarbons in section Pollution Monitoring Instruments of Analytical Instrumentation
Answer» Right option is (c) 0-20 ppm The best I can explain: In flame ionization detectors, the range ADEQUATE for atmospheric SAMPLING is 0-20ppm. It is USEFUL for DETECTING ORGANIC compounds.

Discussion

43.	In flame ionization detector, the ions collected on the negatively charged grid are amplified at the high impedance amplifier.(a) True(b) FalseThis question was posed to me in an online quiz.This key question is from Estimation of Hydrocarbons topic in portion Pollution Monitoring Instruments of Analytical Instrumentation
Answer» Correct choice is (b) False The BEST I can EXPLAIN: In flame ionization detector, the IONS collected on the positively charged grid are amplified at the high impedance amplifier. Its output is GIVEN to the chart recorder.

Discussion

44.	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-photometryI had been asked this question by my school teacher while I was bunking the class.This interesting question is from Sulphur Di-oxide Monitoring topic in chapter Pollution Monitoring Instruments of Analytical Instrumentation
Answer» Right CHOICE is (C) Paramagnetic analyzers Explanation: Sulphur di-oxide cannot be analysed using paramagnetic ANALYZER. This is because sulphur DIOXIDE does not have paramagnetic PROPERTY.

Discussion

45.	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 acidThe question was asked by my school teacher while I was bunking the class.The query is from Estimation of Nitrogen Oxides topic in portion Pollution Monitoring Instruments of Analytical Instrumentation
Answer» Right CHOICE is (d) Phosphoric acid For EXPLANATION: In Jacob-Hochheiser method, NO2 is passed through a dilute solution of SODIUM hydroxide to FORM the NITRITE ion. The nitrite ion is treated with sulphanilamide and ethylene diamine in phosphoric acid to form the highly coloured azo dye. Then, colorimetric analysis is done.

Discussion

Explore topic-wise InterviewSolutions in .

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 ppmI got this question in semester exam.My doubt is from Sulphur Di-oxide Monitoring in chapter Pollution Monitoring Instruments of Analytical Instrumentation

Hydrogen flame ionization detector can be used to detect only the peak of CO and not methane.(a) True(b) FalseI have been asked this question during an interview.This interesting question is from Estimation of Carbon Monoxide in section Pollution Monitoring Instruments of Analytical Instrumentation

Propane would give three times the intensity of response as compared to methane.(a) True(b) FalseI have been asked this question during an interview for a job.This question is from Estimation of Hydrocarbons topic in section Pollution Monitoring Instruments of Analytical Instrumentation

The response of coulometric method is instantaneous.(a) True(b) FalseI have been asked this question in an online interview.My question is taken from Sulphur Di-oxide Monitoring topic in section Pollution Monitoring Instruments of Analytical Instrumentation

CO laser is operated at liquid nitrogen temperature.(a) True(b) FalseI have been asked this question in homework.I want to ask this question from Estimation of Nitrogen Oxides topic in portion Pollution Monitoring Instruments of Analytical Instrumentation

West-Gaeke colorimetric method is used to analyse oxides of nitrogen.(a) True(b) FalseThis question was posed to me during an online exam.The doubt is from Estimation of Nitrogen Oxides in portion Pollution Monitoring Instruments of Analytical Instrumentation