R4RIN – MCQs, Mock Tests | Analytical instruments Analytical Instrumentation MCQ Question Set 5

Which is the compound that forms the stain in Lead Acetate Tape Staining method used for the analysis of Hydrogen Sulphide and what is the colour of the stain?

1. Lead Sulphide, red colour
2. Lead Sulphide, brown colour
3. Hydrogen acetate, white colour
4. Hydrogen acetate, green colour

✅ Correct Answer: 2

Which of the following methods is not used for detection of hydrogen sulphide?

1. Lead acetate tape staining method
2. Solid state sensor
3. Chemiluminescence method
4. Electrochemical cells

✅ Correct Answer: 3

In solid state sensor, when heated to 150o to 300o which of the following occurs?

1. Resistance decreases with increase in H2S concentration
2. Resistance increases with H2S concentration
3. No change in resistance occurs
4. Sensor does not respond in this temperature range

✅ Correct Answer: 1

In the gold film sensor, the change in resistance is proportional to the concentration of H2S.

1. True
2. False
3. all of the above
4. None of the mentioned

✅ Correct Answer: 1

Which of the following occurs in Electrochemical cells used for the detection of hydrogen sulphide?

1. Change in resistance
2. Redox reaction
3. Oxidation-reduction reaction
4. Change in colour

✅ Correct Answer: 3

Which of the following is not a component of solid state sensor used for detection of hydrogen sulphide?

1. Heater
2. Thermistor
3. Semiconductor film
4. Photo detector

✅ Correct Answer: 4

Which of the following is not a detector used in mid Infrared Spectrophotometer?

1. Thermopile
2. Thermistor
3. Pyroelectric cell
4. Golay cell

✅ Correct Answer: 4

Why is the use of infrared analyzers limited when it comes to the analysis of inorganic compounds?

1. Slow response occurs
2. Less accurate results occur
3. Strong absorption of IR radiation by water
4. Small range

✅ Correct Answer: 3

Which of the following is the chopping frequency used for industrial analyzers in the simple infrared analyser for gas analysis?

1. 2-10 Hz
2. 2-50 Hz
3. 2-100 Hz
4. 2-150 Hz

✅ Correct Answer: 1

Which of the following is used as a source in the simple infrared analyzer for gas analysis?

1. Tungsten filament lamp
2. Nernst glower
3. Hot-wire spiral
4. Mercury arc lamp

✅ Correct Answer: 3

Vibration excitation occurs only if the sample has hetero-atomic molecules.

1. True
2. False
3. all of the above
4. None of the mentioned

✅ Correct Answer: 1

Which of the following is the relationship between the density of ideal gas and its molecular weight?

1. Directly proportional
2. Inversely proportional
3. Linear
4. No relation

✅ Correct Answer: 3

Under which of the following conditions do all real gases behave as ideal gases to some extent?

1. Low temperature and low pressure
2. Low temperature and high pressure
3. High temperature and low pressure
4. Room temperature and normal pressure

✅ Correct Answer: 4

Which of the following detectors are not used in analyzers based on gas density?

1. Hot wire
2. Platinum filament
3. Thermistor
4. Thermometer

✅ Correct Answer: 4

When would the recorder indicate a zero base line in analyzers based on gas density?

1. When the detector on the sample side is cooler than that on the reference side
2. When the detector on the reference side is cooler than that on the sample side
3. When flow is unbalanced
4. When both the detectors are equally cooled

✅ Correct Answer: 4

The use of thermistor eliminates the requirement for amplification.

1. True
2. False
3. all of the above
4. None of the mentioned

✅ Correct Answer: 1

In analyzers based on gas density, the unbalance of the bridge is linearly proportional to which of the following?

1. Temperature of sample detector
2. Pressure at sample detector
3. Pressure difference between both the detectors
4. Gas-density difference between both the detectors

✅ Correct Answer: 4

Which of the following bridges are used in analyzers based on gas density?

1. Wheatstone bridge
2. Kelvin’s bridge
3. Anderson’s bridge
4. Schering’s bridge

✅ Correct Answer: 1

In analyzers based on gas density, if the sample carries a gas having a higher density than the detector which of the following occurs?

1. It will cause a net downward flow
2. It will cause a net upward flow
3. It splits into two beams
4. There will be no difference in flow

✅ Correct Answer: 1

When hot-wires are used as detectors amplification is not required.

1. True
2. False
3. all of the above
4. None of the mentioned

✅ Correct Answer: 2

Which of the following is the effective sample volume in analyzers based on gas density?

1. 10 ml
2. 20 ml
3. 5 ml
4. 50 ml

✅ Correct Answer: 3

Gases emit radiation under which of the following conditions which can be used for determination of gases?

1. When mixed with other gases
2. When kept at suitable temperature
3. With sufficient electrical excitation and at suitable pressures
4. When exposed to radiation

✅ Correct Answer: 3

Which of the following measuring technique is utilized for measuring nitrogen?

1. By using a method based on gas density
2. By using a method based on gas density
3. By using magnetic wind instruments
4. By using a photospectrometer where a gas sample is analysed and detected with a photocell

✅ Correct Answer: 4

The characteristic emission of which colour, when discharge takes place in a low pressure chamber containing gas sample, will indicate the presence of nitrogen while using photospectrometer?

1. Purple
2. Blue
3. Pink
4. Green

✅ Correct Answer: 1

Sample rates of nitrogen meter can be adjusted by doing which of the following?

1. By modifying the amplifier
2. With the help of the needle valve
3. By modifying the detector
4. By changing chopper frequency

✅ Correct Answer: 2

Which of the following is the normal sampling rate used in nitrogen meters?

1. 13 ml/min
2. 33 ml/min
3. 3 ml/min
4. 43 ml/min

✅ Correct Answer: 3

Nitrogen meters are calibrated for which of the following to measure nitrogen?

1. Mixture of nitrogen and air
2. Water saturated mixture of nitrogen and oxygen
3. Mixture of nitrogen and hydrogen
4. nitrogen

✅ Correct Answer: 2

Why is nitrogen meters generally not calibrated for dry gases while measuring nitrogen?

1. It causes error
2. Range decreases
3. Reading tend to be non-linear
4. It cannot be measured

✅ Correct Answer: 1

In which of the following ways can nitrogen be calibrated for dry gases?

1. By modifying the amplifier
2. By adjusting the needle valve
3. By modifying the detector
4. By changing chopper frequency

✅ Correct Answer: 2

The voltage required for striking the discharge in the presence of nitrogen is 1500V.

1. True
2. False
3. all of the above
4. None of the mentioned

✅ Correct Answer: 1

The light output from the discharge tube is interrupted by means of a rotating slotted disc.

1. True
2. False
3. all of the above
4. None of the mentioned

✅ Correct Answer: 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?

1. Sodium tetra chloromercurate
2. Dicholorosulphitomercurate complex
3. Ammonia molybdate
4. Paraosaniline sulphonic acid

✅ Correct Answer: 4

The conductivitimetry method, involves bubbling sulphur dioxide through a solution containing sulphuric acid and which of the following?

1. Water
2. Hydrogen peroxide
3. Iodine
4. Formaldehyde

✅ Correct Answer: 2

Which of the following are not the characteristics of conductivitimetry method used to measure sulphur dioxide?

1. Fast response
2. High sensitivity
3. Free from interference by other gases
4. Good accuracy

✅ Correct Answer: 3

Which of the following are not the characteristics of colorimetry method used to monitor sulphur dioxide?

1. It is simple
2. It has high sensitivity
3. It has good specificity
4. It is affected by interference from H2SO4, SO3, NH3, etc

✅ Correct Answer: 4

Which of the following is not true about using gas chromatography for measuring pollutants in the air?

1. Pollutants react rapidly in the column
2. Pollutants may not be detected by the detectors
3. Special column and support materials are required
4. Pollutants may elude rapidly from the column

✅ Correct Answer: 4

The ability of sulphur dioxide to reduce iodine is used in which of the following methods?

1. Colorimetry
2. Conductivitimetry
3. Coulometry
4. Gas chromatography

✅ Correct Answer: 3

Which of the following materials are used as electrodes in the coulometric method for the measurement of sulphur dioxide?

1. Gold
2. Silver
3. Platinum
4. Nickel

✅ Correct Answer: 3

Which of the following is the detection limit of the coulometric method used for measurement of sulphur dioxide?

1. 0.1 ppm
2. 1 ppm
3. 2 ppm
4. 0.01 ppm

✅ Correct Answer: 4

Sensitivity to total sulphur by Flame-photometric detector is which of the following levels?

1. 0.1 ppm
2. 1 ppm
3. 2 ppm
4. 0.01 ppm

✅ Correct Answer: 4

Which of the following methods are not used for the measurement of sulphur dioxide?

1. Colorimetric method
2. Correlation spectroscopy
3. Paramagnetic analyzers
4. Flame-photometry

✅ Correct Answer: 3

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?

1. 243 nm
2. 394 nm
3. 467 nm
4. 516 nm

✅ Correct Answer: 2

In conductivitimetric method, the concentration of sulphur dioxide is proportional to which of the following parameters of the saw-tooth waveform?

1. Average voltage
2. Peak voltage
3. Slope
4. RMS voltage

✅ Correct Answer: 3

In the conductivitimetric method, to measure the conductivity of the cell, 5V ___________ is applied across the electrodes.

1. DC
2. AC
3. Pulsating DC
4. DC or AC

✅ Correct Answer: 2

The response of coulometric method is instantaneous.

1. True
2. False
3. all of the above
4. None of the mentioned

✅ Correct Answer: 2

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?

1. Blue colour dye complex
2. Green colour dye complex
3. Pink colour dye complex
4. Orange colour dye complex

✅ Correct Answer: 3

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?

1. Less accuracy
2. Dye formed is unstable
3. Dye formed is colourless
4. Quantity of dye is low

✅ Correct Answer: 2

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?

1. Sulphuric acid
2. Hydrochloric acid
3. Nitric acid
4. Phosphoric acid

✅ Correct Answer: 4

Which of the following methods results in the formation of yellow coloured compound?

1. Griess-Saltzman method
2. Phenoldisul phonoic acid method
3. Chemiluminescence method
4. West-Gaeke method

✅ Correct Answer: 2

Which of the following is the most common application of Chemiluminescence method used for the analysis of Nitrogen oxides?

1. In medical applications
2. In automotive exhaust gases
3. In manufacturing processes
4. In chemical industries

✅ Correct Answer: 2