117 + Interview Questions in Ph Meters And Ion Analysers in Analytical Instrumentation Page 1 InterviewSolution

1.	Which of the following is the formula for pH calculation?(a) log10[H+](b) -log10[H+](c) log2[H+](d) -log2[H+]I have been asked this question by my school teacher while I was bunking the class.Enquiry is from pH Measurement and Types in division pH Meters and Ion Analysers of Analytical Instrumentation
Answer» Right choice is (B) -log10[H+] EASIEST explanation: pH is defined as the negative logarithm of HYDROGEN ion concentration. Hence, its formula is -log10[H+].

Discussion

2.	Which of the following is not the disadvantage of hydrogen electrode?(a) Platinum can be easily poisoned(b) Presence of oxidising agents alters the potential(c) It gives a salt error(d) H2 gas at 1 atmospheric pressure is difficult to set up and transportI got this question in a job interview.I'd like to ask this question from Hydrogen and Glass Electrodes topic in section pH Meters and Ion Analysers of Analytical Instrumentation
Answer» Right answer is (c) It gives a SALT ERROR Easy EXPLANATION: Hydrogen electrode does not give a salt error. A number of hydrogen electrodes are AVAILABLE.

Discussion

3.	Combination electrodes containing the electrolyte in gel format have which of the following advantages over normal ones?(a) Simple to use(b) Low maintenance(c) Low cost(d) More accurateI have been asked this question in class test.The query is from Combination Electrode topic in chapter pH Meters and Ion Analysers of Analytical Instrumentation
Answer» Correct option is (b) LOW maintenance For explanation I would SAY: COMBINATION ELECTRODES containing the electrolyte in gel format PROVIDE the advantage of low maintenance. They are more rugged.

Discussion

4.	Which of the following is not the characteristics of a calomel electrode?(a) The potential of electrode is not temperature dependent(b) Preparation of electrode is easy(c) Value of potential or emf is higher for lower concentration of Kcl(d) Value of potential decreases with increasing concentration of KclThe question was asked in an interview.I would like to ask this question from Secondary Reference Electrodes in section pH Meters and Ion Analysers of Analytical Instrumentation
Answer» Right CHOICE is (a) The potential of electrode is not temperature dependent Easiest EXPLANATION: The potential of calomel electrode is temperature dependent. When temperature changes potential comes to a new value. It cannot be used in places where high temperatures EXIST.

Discussion

5.	In which of the following solutions must combination electrodes be soaked after cleaning?(a) KCl(b) LiCl(c) KNO3(d) K2SO4This question was addressed to me during an interview for a job.My question is based upon Combination Electrode topic in portion pH Meters and Ion Analysers of Analytical Instrumentation
Answer» The correct choice is (a) KCl The BEST explanation: COMBINATION electrodes can be soaked in KCl SOLUTION after cleaning. This will re-condition the bulb and increases its life.

Discussion

6.	Which of the following is the physico-chemical component?(a) Enzymes(b) Anti-bodies(c) Transducer(d) Cells or tissuesI got this question during an online interview.Asked question is from Biosensors in section pH Meters and Ion Analysers of Analytical Instrumentation
Answer» CORRECT OPTION is (C) Transducer Explanation: Transducer is referred to as the physico-chemical component. ENZYMES and anti-bodies are biological components.

Discussion

7.	Biosensors measure glucose concentrations between which of the following ranges?(a) 10^-1 to 10^-2 M(b) 10^-2 to 10^-4 M(c) 10^-1 to 10^-4 M(d) 10^-1 to 10^-7 MThe question was posed to me during an online exam.I'm obligated to ask this question of Biosensors in section pH Meters and Ion Analysers of Analytical Instrumentation
Answer» Correct option is (d) 10^-1 to 10^-7 M The best I can EXPLAIN: Biosensors MEASURE glucose CONCENTRATIONS between 10^-1 to 10^-7 M. It is LINEAR in the range of 10^-2 to 10^-4 M.

Discussion

8.	Which of the following is not the disadvantage of glass electrodes?(a) Poor readings are obtained in buffered or unbuffered solutions(b) The electrode must be washed thoroughly with distilled water to obtain proper results(c) Materials suspended on glass should be wiped out neatly to obtain proper results(d) It is affected by oxidation reduction potentials in the solutionI got this question in an interview for job.This question is from Hydrogen and Glass Electrodes topic in section pH Meters and Ion Analysers of Analytical Instrumentation
Answer» The CORRECT option is (d) It is AFFECTED by oxidation reduction potentials in the solution The EXPLANATION: It is affected by oxidation reduction potentials in the solution. It is an advantage of the glass ELECTRODE.

Discussion

9.	The calomel electrodes are classified based on which of the following?(a) Materials used in the electrode(b) Amount of mercury present(c) Concentration of Kcl(d) Purity of mercuryI had been asked this question in a national level competition.This interesting question is from Secondary Reference Electrodes topic in division pH Meters and Ion Analysers of Analytical Instrumentation
Answer» The CORRECT OPTION is (c) Concentration of Kcl To elaborate: Several CONVENIENT calomel electrodes are available. They are classified BASED on the concentration of Kcl.

Discussion

10.	The performance of ammonia electrode is not affected by sample colour and turbidity.(a) True(b) FalseThis question was posed to me in final exam.My enquiry is from Ammonia and Fluoride Electrode topic in portion pH Meters and Ion Analysers of Analytical Instrumentation
Answer» CORRECT choice is (a) True Easiest EXPLANATION: The PERFORMANCE of ammonia electrode is not affected by sample colour and turbidity. Temperature AFFECTS its OUTPUT.

Discussion

11.	Which of the following is not the characteristic of null-detector type pH meter?(a) It can be battery operated(b) It has less accuracy(c) It is easy to maintain(d) Its electronic circuits are simpleI have been asked this question in final exam.This key question is from pH Meters in division pH Meters and Ion Analysers of Analytical Instrumentation
Answer» CORRECT option is (b) It has LESS accuracy Explanation: Null-detector TYPE pH meter has greater accuracy than 0.01 pH. pH value is READ from the calibrated precision voltage SOURCE dial.

Discussion

12.	What does TISAB which is used to overcome interferences stand for?(a) Total Isolation Strength Absolute Buffer(b) Total Ionic Strength Absolute Buffer(c) Total Ionic Strength Adjustment Buffer(d) Total Isolation Strength Adjustment BufferThis question was addressed to me in an interview for job.The query is from Ammonia and Fluoride Electrode topic in section pH Meters and Ion Analysers of Analytical Instrumentation
Answer» The correct option is (c) TOTAL Ionic STRENGTH Adjustment Buffer The best EXPLANATION: TISAB STANDS for ‘Total Ionic Strength Adjustment Buffer’. It is ADDED in excess and in exactly the same amount to each of the solutions that is to be measured.

Discussion

13.	In carbon dioxide electrode, the membrane separates which of the following?(a) Sodium carbonate, magnesium chloride(b) Magnesium hydrogen carbonate, sodium chloride(c) Sodium hydrogen carbonate, sodium chloride(d) Magnesium carbonate, magnesium chlorideI got this question by my college director while I was bunking the class.This intriguing question originated from Special Designs of Ion Selective Electrodes topic in portion pH Meters and Ion Analysers of Analytical Instrumentation
Answer» Right answer is (b) Magnesium HYDROGEN CARBONATE, SODIUM chloride Best explanation: In carbon dioxide electrode, the MEMBRANE separates sodium hydrogen carbonate and sodium chloride. Sodium hydrogen carbonate is the internal electrolyte.

Discussion

14.	Which of the following salt bridge solutions must be used for silver/silver chloride electrode?(a) Saturated KCl(b) Saturated K2SO4(c) Saturated LiCl(d) Saturated KNO3This question was posed to me in an interview.This intriguing question comes from Secondary Reference Electrodes in chapter pH Meters and Ion Analysers of Analytical Instrumentation
Answer» CORRECT choice is (a) SATURATED KCl The best explanation: Saturated KCl is used as the salt bridge solution for silver/silver CHLORIDE ELECTRODE. It can ALSO be used for calomel electrode.

Discussion

15.	Which of the following is not the advantage of glass electrodes?(a) It gives accurate results for high as well as low pH values(b) It is simple to operate(c) It has no salt error(d) Modern electrodes can withstand severe treatmentI got this question by my college professor while I was bunking the class.This interesting question is from Hydrogen and Glass Electrodes in division pH Meters and Ion Analysers of Analytical Instrumentation
Answer» Right option is (a) It gives ACCURATE results for high as WELL as LOW pH values The best EXPLANATION: It gives accurate results for low pH values only ie. from 0 to 9. For high pH values, the glass becomes RESPONSIVE to sodium and other cations.

Discussion

16.	The reference electrodes in combination electrodes are protected against light using which of the following?(a) Emerald green glass(b) Ruby red glass(c) Sapphire blue glass(d) Pearl white glassI got this question in examination.Enquiry is from Combination Electrode in chapter pH Meters and Ion Analysers of Analytical Instrumentation
Answer» The correct choice is (b) Ruby RED GLASS The explanation is: The reference electrodes in combination electrodes are PROTECTED against LIGHT using ruby red glass. The ruby red glass ABSORBS light.

Discussion

17.	Which of the following causes main interference in Fluoride electrode?(a) H^+ ions(b) OH^– ions(c) Li^+ ions(d) Cl^– ionsThis question was posed to me in unit test.The doubt is from Ammonia and Fluoride Electrode in chapter pH Meters and Ion Analysers of Analytical Instrumentation
Answer» Correct answer is (b) OH^– IONS To EXPLAIN: The MAIN interference in FLUORIDE ions is caused by OH^– ions. It has excellent selectivity.

Discussion

18.	Which of the following reference electrode is placed in the solution of carbon dioxide electrode?(a) Calomel electrode(b) Silver/silver chloride electrode(c) Mercury/mercury sulphate electrode(d) Glass electrodeThis question was posed to me in an online quiz.My doubt is from Special Designs of Ion Selective Electrodes topic in portion pH Meters and Ion Analysers of Analytical Instrumentation
Answer» The correct ANSWER is (b) Silver/silver CHLORIDE electrode The EXPLANATION: A silver/silver chloride reference electrode is placed in the solution. A glass electrode is ALSO placed in the solution but it is not a reference electrode.

Discussion

19.	Which of the following factors does not the reproducibility of the ammonia electrode?(a) Temperature(b) Drift(c) Noise(d) DilutionThis question was addressed to me in a job interview.My doubt stems from Ammonia and Fluoride Electrode in section pH Meters and Ion Analysers of Analytical Instrumentation
Answer» Right ANSWER is (d) Dilution The best I can EXPLAIN: Dilution does not affect REPRODUCIBILITY. The other THREE factors affect reproducibility.

Discussion

20.	Transducers employed in the bulk of enzyme electrodes use which of the following principles?(a) Amperometric(b) Optical(c) Magnetic(d) ColorimetricI have been asked this question in homework.My doubt stems from Biosensors in portion pH Meters and Ion Analysers of Analytical Instrumentation
Answer» Correct ANSWER is (a) Amperometric Explanation: Transducers employed in the bulk of enzyme electrodes USE amperometric principle. It may ALSO use the POTENTIOMETRIC principle.

Discussion

21.	In Hydrogen electrode, the electrode is placed in a solution of ____ M Hcl. Fill in the blank.(a) 0.5(b) 1(c) 2(d) 3The question was asked in exam.The question is from Hydrogen and Glass Electrodes in division pH Meters and Ion Analysers of Analytical Instrumentation
Answer» RIGHT option is (B) 1 To explain I would say: In Hydrogen electrode, the electrode is placed in a solution of 1M HCL. H2 gas at 1 atm pressure is passed through the side arm in such a way that the platinum is half immersed in Hcl.

Discussion

22.	Beckman coulter gel filled combination electrodes provide which of the following features to overcome various problems that occur in gel filled electrodes?(a) Filters(b) Semi-permeable membrane(c) Gas-permeable membrane(d) Micro-pore junctionThis question was addressed to me during an interview for a job.The doubt is from Combination Electrode in division pH Meters and Ion Analysers of Analytical Instrumentation
Answer» Correct choice is (d) Micro-pore junction The explanation is: Beckman coulter gel FILLED combination ELECTRODE PROVIDES a special micro-pore junction to OVERCOME VARIOUS problems that occur in gel filled electrodes. Here, there is direct contact between the sample and the gel.

Discussion

23.	Which of the following specifies the relation between ionic strength and activity coefficient?(a) Directly proportional(b) Inversely proportional(c) Equal(d) No particular relationThis question was addressed to me during an interview for a job.My query is from Ion Selective Electrodes-Principle and Types topic in division pH Meters and Ion Analysers of Analytical Instrumentation
Answer» RIGHT ANSWER is (b) INVERSELY proportional The explanation: Activity co-efficient and ionic STRENGTH are inversely proportional to each other. If the ionic strength increases, the value of activity decreases.

Discussion

24.	Crystal membrane of ion selective electrode can be regenerated by washing with which of the following?(a) Alcohol(b) Iodine solution(c) Acidic solution(d) Basic solutionI have been asked this question during an interview.Question is taken from Ammonia and Fluoride Electrode topic in division pH Meters and Ion Analysers of Analytical Instrumentation
Answer» Correct answer is (a) ALCOHOL The explanation is: Crystal membrane of an ion SELECTIVE electrode can be REGENERATED by WASHING with alcohol. It can be gently polished with EMERY paper to remove deposits.

Discussion

25.	For fluoride electrode, the electrode response curve will not only shift but will change slope with changes in temperature.(a) True(b) FalseI had been asked this question in quiz.I'd like to ask this question from Ammonia and Fluoride Electrode in section pH Meters and Ion Analysers of Analytical Instrumentation
Answer» The correct choice is (a) True For EXPLANATION: For fluoride electrode, the electrode response CURVE will not only shift but will CHANGE slope with changes in temperature. A 1o change in temperature causes a 2% error.

Discussion

26.	During which of the following conditions is the blank correction not necessary?(a) If sample concentration rises in linear response region(b) If sample concentration falls in linear response region(c) If sample concentration rises in non-linear response region(d) If sample concentration falls in non-linear response regionThe question was asked in quiz.This question is from Ion Analyser topic in section pH Meters and Ion Analysers of Analytical Instrumentation
Answer» Right ANSWER is (b) If sample concentration FALLS in linear RESPONSE region The EXPLANATION is: The blank correction is not NECESSARY if sample concentration falls in the linear response region. This is the constant background for all measurements.

Discussion

27.	The analog and digital grounds are connected together in ion analysers.(a) True(b) FalseI had been asked this question in an online quiz.My doubt is from Ion Analyser in chapter pH Meters and Ion Analysers of Analytical Instrumentation
Answer» RIGHT option is (b) False The explanation is: The analog and DIGITAL grounds are not connected together in ion ANALYSERS. This is to ensure that the digital SIGNALS NEVER flow through the same conductor as analog signals.

Discussion

28.	Which of the following is the value of hydrogen ion concentration of pure water?(a) 1×10^7 moles/litre(b) 1×10^5 moles/litre(c) 1×10^6 moles/litre(d) 1×10^8 moles/litreI have been asked this question in an international level competition.My doubt is from pH Measurement and Types topic in division pH Meters and Ion Analysers of Analytical Instrumentation
Answer» RIGHT OPTION is (a) 1×10^7 moles/litre For EXPLANATION I would SAY: The hydrogen ION concentration of pure water is 1×10^7 moles/litre. It can be represented as [H+]=1×10^7 moles/litre.

Discussion

29.	Which of the following is the purpose of added membranes in the glass membrane of the glass electrode?(a) They act as tightners(b) They act as filters(c) They act as conditioners(d) They act as collectorsThe question was asked in a national level competition.Enquiry is from Hydrogen and Glass Electrodes topic in portion pH Meters and Ion Analysers of Analytical Instrumentation
Answer» Right CHOICE is (a) They act as tightners The best EXPLANATION: The ions in the ADDED MEMBRANES act as tightners. They REDUCE the mobility of sodium ion.

Discussion

30.	Which of the following calomel electrodes are used for accurate work?(a) Saturated calomel electrode(b) Electrode with 0.1M Kcl(c) Electrode with 1M Kcl(d) Electrode with 2M KclI got this question in examination.Enquiry is from Secondary Reference Electrodes topic in section pH Meters and Ion Analysers of Analytical Instrumentation
Answer» The correct option is (B) Electrode with 0.1M Kcl Explanation: CALOMEL electrode with 0.1M Kcl is USED for accurate WORK. Saturated calomel electrodes are easy to prepare and MAINTAIN.

Discussion

31.	Gel filled combination electrodes operate in a wide temperature range.(a) True(b) FalseThis question was posed to me in final exam.I'd like to ask this question from Combination Electrode in chapter pH Meters and Ion Analysers of Analytical Instrumentation
Answer» RIGHT CHOICE is (a) True To explain: GEL FILLED combination electrodes operate in a wide temperature range. The temperature range is between -5 to 100^oC.

Discussion

32.	Good choice for storing combination electrodes is in a buffer solution having which of the following pH?(a) pH1(b) pH2(c) pH3(d) pH4I had been asked this question by my college professor while I was bunking the class.Question is taken from Combination Electrode in section pH Meters and Ion Analysers of Analytical Instrumentation
Answer» Right option is (d) PH4 The explanation is: Good choice for STORING COMBINATION electrodes is in a buffer SOLUTION having pH4. They can be stored in KCL solutions having particular pH values.

Discussion

33.	Which of the following is not a failure in pH meters?(a) Defective electrodes(b) Defective input circuitry(c) Defective electronic circuitry(d) Defective calibrationThis question was addressed to me in final exam.This interesting question is from pH Meters in section pH Meters and Ion Analysers of Analytical Instrumentation
Answer» Right answer is (d) Defective calibration For explanation I WOULD say: Defective calibration is not a failure in pH METERS. Failure occurs due to defective electrodes, defective INPUT circuitry and defective ELECTRONIC circuitry.

Discussion

34.	Which of the following is not a problem of ion selective electrodes?(a) Interference with other ions(b) Output is influences by ionic strength(c) Drift in electrode potential during a sequence of measurements(d) Can measure only positive ionsThe question was asked during an interview for a job.This intriguing question comes from Ion Selective Electrodes-Principle and Types in division pH Meters and Ion Analysers of Analytical Instrumentation
Answer» Right CHOICE is (d) Can measure only positive IONS To explain: Ion selective ELECTRODES can measure both positive and negative ions. It is AFFECTED by INTERFERENCE from other ions.

Discussion

35.	In ion analysers, which of the following serve the dual purpose of controlling the operating current of FET and providing current gain?(a) FET itself does it(b) SCR(c) Op-amp(d) DiodeI have been asked this question in a national level competition.My question comes from Ion Analyser topic in portion pH Meters and Ion Analysers of Analytical Instrumentation
Answer» CORRECT answer is (c) Op-amp Explanation: In ion analysers, op-amp SERVES the dual purpose of controlling the operating CURRENT of FET and providing current gain. TWO FETs are operated as source FOLLOWERS.

Discussion

36.	Which of the following biosensors use the movement of electrons produced during redox reactions?(a) Amperometric biosensor(b) Potentiometric biosensors(c) Piezo-electric biosensors(d) Optical biosensorsThis question was addressed to me during an online exam.This key question is from Biosensors in chapter pH Meters and Ion Analysers of Analytical Instrumentation
Answer» CORRECT answer is (a) Amperometric BIOSENSOR The best I can explain: Amperometric biosensor uses the movement of electrons produced during REDOX REACTIONS. Redox reactions involve both reduction and OXIDATION.

Discussion

37.	The presence of dirt or moisture degrades which of the following?(a) Circuit components(b) High input impedance of buffer amplifier(c) Low input impedance of buffer amplifier(d) Low output impedance of buffer amplifierThe question was posed to me in final exam.The doubt is from Ion Analyser topic in section pH Meters and Ion Analysers of Analytical Instrumentation
Answer» Right choice is (B) High input impedance of buffer amplifier To explain I would say: The presence of DIRT or moisture degrades the high input impedance of the buffer amplifier. Solder flux MAY ALSO degrade it.

Discussion

38.	Which of the following is not the characteristic of direct reading type pH meters?(a) Simple operation(b) Quick to use(c) Continuous indication output(d) It requires balancing processI have been asked this question in an interview for job.I'm obligated to ask this question of pH Meters in section pH Meters and Ion Analysers of Analytical Instrumentation
Answer» Right ANSWER is (d) It requires balancing process For explanation: Direct reading type pH METERS do not REQUIRE balancing process. Its operation is simple and readings can be READ directly.

Discussion

39.	In which of the following ways can the disadvantages of chopper amplifier type pH meter be overcome?(a) Using zero corrected DC amplifier(b) Using modern design(c) Using digital design(d) Using vibrating condenserI got this question in final exam.This intriguing question originated from pH Meters topic in portion pH Meters and Ion Analysers of Analytical Instrumentation
Answer» Correct option is (d) USING vibrating condenser Best explanation: The disadvantages of CHOPPER amplifier TYPE pH meter can be overcome using a vibrating condenser. It is USED in the place of the mechanical chopper.

Discussion

40.	In liquid membrane electrode, the liquid ion exchanger is held in a porous disc of _____________(a) Solid material(b) Semi-permeable membrane(c) Hydrophobic material(d) Water absorbing materialI had been asked this question in an international level competition.My enquiry is from Ion Selective Electrodes-Principle and Types in division pH Meters and Ion Analysers of Analytical Instrumentation
Answer» CORRECT CHOICE is (c) HYDROPHOBIC material The BEST explanation: In a liquid membrane electrode, the liquid ion EXCHANGER is held in a porous disc of hydrophobic material. It is water repelling material.

Discussion

41.	In solid state membranes, the body of the electrodes are made of which of the following?(a) Polyvinyl chloride(b) Plastic(c) Polythene(d) TeflonI have been asked this question in semester exam.My question is from Ion Selective Electrodes-Principle and Types topic in portion pH Meters and Ion Analysers of Analytical Instrumentation
Answer» Correct option is (d) Teflon Easiest explanation: In SOLID state MEMBRANES, the body of the electrodes are made of Teflon. The membrane is held in position USING EPOXY RESIN.

Discussion

42.	The value of activity coefficient is always in which of the following ranges?(a) Zero(b) Less than zero(c) Less than 1(d) Greater than 1This question was posed to me by my school teacher while I was bunking the class.My query is from Ion Selective Electrodes-Principle and Types topic in portion pH Meters and Ion Analysers of Analytical Instrumentation
Answer» Correct option is (c) LESS than 1 To ELABORATE: The value of activity coefficient is ALWAYS less than 1. It is the ratio of activity divided by concentration.

Discussion

43.	The difference between measured activity and actual concentration becomes higher at higher concentration. Is this statement true or false?(a) True(b) FalseThe question was asked in unit test.Query is from Ion Selective Electrodes-Principle and Types topic in division pH Meters and Ion Analysers of Analytical Instrumentation
Answer» The CORRECT answer is (a) True The explanation is: The DIFFERENCE between measured activity and actual concentration becomes HIGHER at higher concentration. Similarly, it decreases at LOWER CONCENTRATIONS.

Discussion

44.	In Ammonia electrode, diffusion of dissolved ammonia occurs through the membrane until which of the following conditions occur?(a) Concentration becomes equal on both sides(b) Activity becomes equal on both sides(c) Partial pressure becomes equal on both sides(d) Differential pressure is lowThe question was posed to me in an internship interview.The query is from Ammonia and Fluoride Electrode topic in portion pH Meters and Ion Analysers of Analytical Instrumentation
Answer» The correct choice is (c) PARTIAL PRESSURE becomes EQUAL on both sides For explanation I would say: In Ammonia ELECTRODE, diffusion of dissolved ammonia occurs through the membrane until partial pressure becomes equal on both sides. Partial pressure is PROPORTIONAL to its concentration.

Discussion

45.	How can samples above 1M in ammonia concentration be measured using ammonia electrode?(a) It must be diluted and measured(b) It cannot be measured(c) The electrode has to be modified for measuring(d) It can be measured directlyThe question was asked in my homework.Enquiry is from Ammonia and Fluoride Electrode in division pH Meters and Ion Analysers of Analytical Instrumentation
Answer» The correct ANSWER is (a) It MUST be diluted and measured Easy explanation: Samples above 1M in ammonia concentration be measured by diluting the solution. Samples having concentrations below that can be measured DIRECTLY.

Discussion

46.	Which of these biosensors use the principle of heat released or absorbed by a reaction?(a) Potentiometric biosensor(b) Optical biosensors(c) Piezo-electric biosensors(d) Calorimetric biosensorsThe question was asked in a national level competition.This intriguing question originated from Biosensors in portion pH Meters and Ion Analysers of Analytical Instrumentation
Answer» Correct answer is (d) CALORIMETRIC BIOSENSORS To EXPLAIN: Calorimetric biosensors USE the principle of heat released or absorbed by a REACTION. The heat is measured to determine the concentration.

Discussion

47.	Which of the following is the relation between hydrogen and hydroxyl ion concentration of pure water?(a) Value of hydrogen ion concentration is greater(b) Value of hydroxyl ion concentration is greater(c) They are both always the same(d) The concentrations keep changingThe question was posed to me in exam.The question is from pH Measurement and Types in division pH Meters and Ion Analysers of Analytical Instrumentation
Answer» The correct ANSWER is (c) They are both ALWAYS the same Best EXPLANATION: In water, the value of HYDROGEN and HYDROXYL ion concentrations are the same. It can be represented as [H+]=[OH-].

Discussion

48.	The pH response of glass electrode is limited entirely to the area of the special glass membrane bulb.(a) True(b) FalseI have been asked this question in homework.My question comes from Hydrogen and Glass Electrodes in division pH Meters and Ion Analysers of Analytical Instrumentation
Answer» Correct option is (a) True Best explanation: The pH response of glass electrode is limited entirely to the area of the SPECIAL glass membrane BULB. The response of the electrode is INDEPENDENT of the DEPTH of IMMERSION.

Discussion

49.	Which of the following is not the characteristic of a reference electrode?(a) It must have a known output potential(b) It must have a constant output potential(c) Its output potential is dependent on the composition of the solution(d) It is employed in conjunction with the indicator or working electrodeI had been asked this question in an interview for job.My doubt stems from Hydrogen and Glass Electrodes topic in section pH Meters and Ion Analysers of Analytical Instrumentation
Answer» Right choice is (c) Its OUTPUT POTENTIAL is DEPENDENT on the composition of the solution To ELABORATE: The output potential of a reference electrode MUST be insensitive to the composition of the solution.

Discussion

50.	Which of the following gas permeable membrane is used for carbon dioxide gas sensing electrode?(a) Silicon rubber(b) PVC membrane(c) Fluorocarbon(d) PolytheneThis question was addressed to me in an online interview.The above asked question is from Special Designs of Ion Selective Electrodes in division pH Meters and Ion Analysers of Analytical Instrumentation
Answer» RIGHT answer is (a) Silicon RUBBER Easy explanation: Gas PERMEABLE membrane used for carbon DIOXIDE SENSING electrode is silicon rubber membrane. For each gas different membranes are used.

Discussion

Explore topic-wise InterviewSolutions in .

Which of the following is the physico-chemical component?(a) Enzymes(b) Anti-bodies(c) Transducer(d) Cells or tissuesI got this question during an online interview.Asked question is from Biosensors in section pH Meters and Ion Analysers of Analytical Instrumentation

The performance of ammonia electrode is not affected by sample colour and turbidity.(a) True(b) FalseThis question was posed to me in final exam.My enquiry is from Ammonia and Fluoride Electrode topic in portion pH Meters and Ion Analysers of Analytical Instrumentation

Which of the following causes main interference in Fluoride electrode?(a) H^+ ions(b) OH^– ions(c) Li^+ ions(d) Cl^– ionsThis question was posed to me in unit test.The doubt is from Ammonia and Fluoride Electrode in chapter pH Meters and Ion Analysers of Analytical Instrumentation

Transducers employed in the bulk of enzyme electrodes use which of the following principles?(a) Amperometric(b) Optical(c) Magnetic(d) ColorimetricI have been asked this question in homework.My doubt stems from Biosensors in portion pH Meters and Ion Analysers of Analytical Instrumentation

In Hydrogen electrode, the electrode is placed in a solution of ____ M Hcl. Fill in the blank.(a) 0.5(b) 1(c) 2(d) 3The question was asked in exam.The question is from Hydrogen and Glass Electrodes in division pH Meters and Ion Analysers of Analytical Instrumentation

The analog and digital grounds are connected together in ion analysers.(a) True(b) FalseI had been asked this question in an online quiz.My doubt is from Ion Analyser in chapter pH Meters and Ion Analysers of Analytical Instrumentation

Gel filled combination electrodes operate in a wide temperature range.(a) True(b) FalseThis question was posed to me in final exam.I'd like to ask this question from Combination Electrode in chapter pH Meters and Ion Analysers of Analytical Instrumentation

The pH response of glass electrode is limited entirely to the area of the special glass membrane bulb.(a) True(b) FalseI have been asked this question in homework.My question comes from Hydrogen and Glass Electrodes in division pH Meters and Ion Analysers of Analytical Instrumentation