250+ MCQs on Instrumentation and Control – Dissolved Oxygen Monitoring and Answers

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Fermentation Technology Multiple Choice Questions on “Instrumentation and Control – Dissolved Oxygen Monitoring”.

1. The details of steam-sterilized electrodes was given by ________
A. Lee and Tsao
B. Kell et al.
C. Schwan
D. Buhler and Ingoldid5fdbe7215bf86″

Answer: A
Clarification: Lee and Tsao in 1979 gave the details of steam sterilized oxygen electrodes. Those electrodes were useful for the measurement of oxygen concentration. It measures the partial pressure of dissolved oxygen.

2. The probe signal of O2 is determined by the equation ____________
A. P(O2) = C(O2) * TP
B. P(O2) = C(O2) * PT
C. P(O2) = C(O2) / PT
D. P(O2) = C(O2) + PTid5fdbe7215bfa5″

Answer: B
Clarification: The probe signal of O2 is determined by the equation: P(O2) = C(O2) * PT where P(O2) is the partial pressure of dissolved oxygen sensed by the probe, C(O2) is the volume or mole fraction of oxygen in the gas phase, and PT is the total pressure.

3. Which of the following acts as the anode in the galvanic electrode?
A. Silver
B. Magnesium
C. Lead
D. Platinumid5fdbe7215bfb3″

Answer: C
Clarification: Lead acts as the anode in the galvanic electrode whereas silver acts as the cathode. The galvanic electrode is used in the measurement of the partial pressure of the dissolved oxygen (DO) concentration.

4. Which of the following is used as an electrolyte in the galvanic electrode?
A. NaCl
B. KCl
C. SnCl2
D. MgCl2id5fdbe7215bfbe”

Answer: B
Clarification: Potassium Chloride is used as an electrode in a galvanic electrode. However, Potassium hydroxide or bicarbonate or acetate is an alternative to Potassium chloride.

5. Which of the following is not used in DO measurement?
A. Polarographic electrode
B. Tubing method
C. Tachometers
D. Galvanic electrodeid5fdbe7215bfc7″

Answer: C
Clarification: The tachometer is used in the measurement of pressure. The tubing method, polarographic electrode, galvanic electrode, etc are used in the measurement of dissolved oxygen concentration.

6. Which of the following method is uses fluorescence for oxygen measurement?
A. Tubing method
B. Fluorometric method
C. Polarographic method
D. Galvanic methodid5fdbe7215bfd1″

Answer: B
Clarification: The fluorometric method uses fluorescence phenomena for the measurement of dissolved oxygen. It has a fast response and is based on the fact that change in the partial pressure of oxygen quenches the fluorescence lifetime of a chromophore.

7. Which of the following is not the type of paramagnetic gas analyzers?
A. Magnetodynamic
B. Thermomagnetic
C. Magnetopneumatic
D. Load cellsid5fdbe7215bfda”

Answer: D
Clarification: The load cells are the cells used for determining the weight of the fermenter vessel. The paramagnetic gas analyzers are of three types: magnetodynamic, thermomagnetic, and magnetopneumatic.

8. Which of the following has a dumbbell shape?
A. Magnetodynamic
B. Thermomagnetic
C. Magnetopneumatic
D. Load cellsid5fdbe7215bfe2″

Answer: A
Clarification: The magnetodynamic type is of the shape of a dumbbell. It is a type of gas analyzer which is used for the measurement of dissolved oxygen.

9. Which of the following is not used for monitoring the pH?
A. Glass electrode
B. Galvanic electrode
C. Silver electrode
D. Combined electrodeid5fdbe7215bfec”

Answer: B
Clarification: The galvanic electrode is used in the measurement of dissolved oxygen. Whereas, glass electrodes, silver electrodes, combined electrodes are used in the measurement of pH of a solution.

10. Which of the following makes contact with a solution whose pH is to be measured?
A. Ceramic plug
B. Electrolyte
C. Silver wire
D. Reference solutionid5fdbe7215bff5″

Answer: A
Clarification: The ceramic plug or bulb is the part of an electrode which makes the contact with the solution whose pH is to be measured. Electrolyte, Silver wire, Reference solution are the part of pH electrodes.

11. What is the value of Faraday’s constant?
A. 96500 J/mol
B. 96400 J/mol
C. 36300 J/mol
D. 36500 J/molid5fdbe7215bffe”

Answer: A
Clarification: The value of Faraday’s constant is 96500 J/mol. It was a constant named after famous scientist Michael Faraday. The Faraday constant equals 1 Faraday of charge per mole.

12. pH is the measurement of _________
A. concentration of H+
B. concentration of H–
C. concentration of OH+
D. concentration of OH–id5fdbe7215c006″

Answer: A
Clarification: The pH is the measurement of H+ ions in the solution. The pH scale was given by Sorenson. pH scale consists of numbers 1 to 14 with a pH of 1 being most acidic and 14 being most basic. pH 7 is a neutral solution.

13. Thermomagnetic is a ‘wind type’ analyzer.
A. True
B. Falseid5fdbe7215c00f”

Answer: A
Clarification: Thermomagnetic is a wind type gas analyzer used for the measurement of dissolved oxygen concentration. It is the measure of magnetic susceptibility of the substance that is magnetized.

14. Nitric oxide exhibits the paramagnetic property.
A. True
B. Falseid5fdbe7215c018″

Answer: A
Clarification: Nitric oxide exhibits the paramagnetic property and has the ability to get attracted to the magnetic field. The electrons get weakly magnetized in presence of the magnetic field.

15. Which of the following is a ferromagnetic substance?
A. Cobalt
B. Nitrogen
C. Nitric oxide
D. Heliumid5fdbe7215c020″

Answer: A
Clarification: Cobalt, Iron are examples of a ferromagnetic substance. The electrons aligned themselves in the direction of the magnetic field and are strongly magnetized. Here, Nitrogen is a diamagnetic material and Nitric oxide is a paramagnetic material.