Potentiometry MCQ Quiz Questions And Answers
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Potentiometry is a method of electroanalytical chemistry that is used to find concentration of a solute in a solution. Check out this 'Potentiometry MCQ quiz with questions and answers. You should try this quiz and get to test your knowledge on the topic of potentiometry today. Do you think you'll be able to pass this test? Let's start and see how much score you can make. So, are you ready? Good luck!
- 1.
The electrolyte solution within the glass electrode (ref) of the pH meter is:
- A.
Saturated KCl
- B.
Concentrated HCl
- C.
Dilute KC1
- D.
Dilute HCl
Correct Answer
A. Saturated KClExplanation
The correct answer is saturated KCl because the glass electrode of a pH meter requires a stable and conductive electrolyte solution. Saturated KCl solution is commonly used as it provides a stable reference potential and minimizes the effects of potential changes due to temperature or other factors. It also helps maintain a constant ionic strength and prevents the electrode from drying out. Concentrated HCl, dilute KCl, and dilute HCl are not suitable choices as they may affect the stability and accuracy of the pH measurement.Rate this question:
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- 2.
The reaction that occurs in the electrolyte solution of the pCO2 electrode resulting in a change in pH is:
- A.
CO2 + H20 ----> H2CO3 ----> H+ + HCO3-
- B.
H+ + CO3- ----> H2CO3
- C.
H2CO3 ----> H2O + CO2
- D.
CO2 + H2O -----> 2H+ + CO3-
Correct Answer
A. CO2 + H20 ----> H2CO3 ----> H+ + HCO3-Explanation
The correct answer is CO2 + H20 ----> H2CO3 ----> H+ + HCO3. In this reaction, carbon dioxide (CO2) reacts with water (H2O) to form carbonic acid (H2CO3). Carbonic acid then dissociates into hydrogen ions (H+) and bicarbonate ions (HCO3-). This reaction results in a change in pH because the formation of hydrogen ions increases the acidity of the solution.Rate this question:
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- 3.
Which of the following is NOT associated with a pCO2 electrode:?
- A.
Membrane permeable to CO2
- B.
PH electrode
- C.
Measurement is amperometric
- D.
Measurement is potentiometric
Correct Answer
C. Measurement is amperometricExplanation
The pCO2 electrode is used to measure the partial pressure of carbon dioxide in a solution. It works based on the principle of potentiometry, where a potential difference is generated between the reference electrode and the working electrode. This potential difference is proportional to the pCO2 concentration. Therefore, the statement "Measurement is amperometric" is not associated with a pCO2 electrode because it is a potentiometric measurement.Rate this question:
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- 4.
Electrodes made of pH sensitive glass may be used in the analysis of:
- A.
PCO2
- B.
PO2
- C.
PH
- D.
All of the above
- E.
None of the above
Correct Answer
D. All of the aboveExplanation
Electrodes made of pH sensitive glass are used in the analysis of PCO2, PO2, and pH. These electrodes are designed to measure the concentration of hydrogen ions in a solution, which is directly related to the pH level. By measuring the pH level, these electrodes can provide information about the partial pressure of carbon dioxide (PCO2), the partial pressure of oxygen (PO2), and the overall pH of a solution. Therefore, both options (a) and (c) are correct as they include the analysis of PCO2 and pH.Rate this question:
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- 5.
The EMF of the sample cell is determined by which of the following formulas:
- A.
Ecell = Ecathode + Elj - Eanode
- B.
Ecell = Eanode - Elj - Ecathode
- C.
Ecell = Ecathode - Elj - Eanode
- D.
Ecell = Eanode + Elj - Ecathode
Correct Answer
A. Ecell = Ecathode + Elj - EanodeExplanation
The correct answer is Ecell = Ecathode + Elj - Eanode. This formula is used to calculate the electromotive force (EMF) of a sample cell. The EMF is determined by the difference in potential between the cathode and the anode, with the contribution of the liquid junction potential (Elj) added. This formula takes into account the direction of electron flow and the potential differences at each electrode.Rate this question:
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- 6.
In potentiometry, which of the following is considered the standard electrode?
- A.
Calcium electrode
- B.
Hydrogen electrode
- C.
Potassium electrode
- D.
Copper electrode
Correct Answer
B. Hydrogen electrodeExplanation
The hydrogen electrode is considered the standard electrode in potentiometry because it has a well-defined and reproducible potential. It is used as a reference electrode to measure the potential of other electrodes in a solution. The standard hydrogen electrode consists of a platinum electrode immersed in a solution of 1 M HCl, with hydrogen gas bubbling through it. The potential of the hydrogen electrode is defined as 0 volts at all temperatures, making it an ideal reference point for measuring electrode potentials.Rate this question:
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- 7.
In an electrolytic cell, which of the following is the half-cell where reduction takes place?
- A.
Anode
- B.
Cathode
- C.
Combination electrode
- D.
Electrode response
Correct Answer
B. CathodeExplanation
In an electrolytic cell, reduction takes place at the cathode. The cathode is the electrode where positively charged ions are attracted and gain electrons, leading to a reduction reaction. This is in contrast to the anode, where oxidation occurs and electrons are lost. The combination electrode is a type of electrode that combines both the anode and cathode in one unit, allowing for both oxidation and reduction reactions to occur. The electrode response refers to the overall behavior and characteristics of the electrode in the cell.Rate this question:
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- 8.
Mercury covered by a layer of mercurous chloride in contact with saturated potassium chloride solution is a description of which of the following types of electrodes?
- A.
Sodium
- B.
Calcium
- C.
Silver/silver chloride
- D.
Calomel
Correct Answer
D. CalomelExplanation
The description of mercury covered by a layer of mercurous chloride in contact with saturated potassium chloride solution matches the characteristics of a calomel electrode. Calomel electrodes are commonly used in electrochemical measurements and are made up of a mercury electrode covered by a layer of mercurous chloride (Hg2Cl2) in contact with a saturated potassium chloride (KCl) solution. This electrode is often used as a reference electrode due to its stable and reproducible potential.Rate this question:
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- 9.
Combination electrodes refer to which of the following?
- A.
Reference and testing electrodes are assigned to different compartments closely linked
- B.
Reduction takes place at the anode
- C.
The testing electrode and reference are contained within a single unit
- D.
The calomel electrode is not a good example of a combination electrode.
Correct Answer
C. The testing electrode and reference are contained within a single unitExplanation
Combination electrodes refer to a type of electrode where the testing electrode and reference electrode are contained within a single unit. This means that both electrodes are combined into one device, making it more convenient and efficient for measurements. The use of a combination electrode eliminates the need for separate electrodes and simplifies the measurement process. The calomel electrode mentioned in the question is an example of a combination electrode.Rate this question:
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- 10.
A pH/Blood gas analyzer contains a pH-sensitive_________. Choose all that apply:
- A.
Glass electrode, which consists of silicon dioxide, sodium oxide, and aluminum oxide
- B.
Electrode surface consisting of a polypropylene membrane permeable to H+
- C.
Electrode surface consisting of a polypropylene membrane permeable to H2CO3/CO2
- D.
Glass electrode which is permeable to H+
Correct Answer
A. Glass electrode, which consists of silicon dioxide, sodium oxide, and aluminum oxideExplanation
A and D are correct. A pH electrode monitors changes in H+ concentration, and a glass electrode containing silicon dioxide, sodium, and aluminum oxide is useful for monitoring changes in the concentrations of the blood gases oxygen and carbon dioxide.Rate this question:
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- 11.
Monitoring the current at an electrolytic electrochemical cell that is generated at a fixed voltage and is proportional to the concentration of analyte present in the test sample in solution is referred to as:
- A.
Coulometry
- B.
Potentiometry
- C.
Osmometry
- D.
Amperometry
Correct Answer
D. AmperometryExplanation
Amperometry is the correct answer because it involves monitoring the current at an electrolytic electrochemical cell that is generated at a fixed voltage and is proportional to the concentration of analyte present in the test sample in solution. This technique is commonly used in electrochemical analysis to measure the concentration of various substances. Coulometry, potentiometry, and osmometry are different techniques that are not specifically related to monitoring current in an electrolytic cell.Rate this question:
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- 12.
Incorporation of ____ into a polyvinyl chloride membrane allows for the manufacture of an ion-selective electrode that is highly selective for calcium.
- A.
Di-p-octylphenyl phosphate
- B.
Nonactin
- C.
Valinomycin
- D.
Erythromycin
Correct Answer
A. Di-p-octylpHenyl pHospHateExplanation
The incorporation of di-p-octylphenyl phosphate into a polyvinyl chloride membrane allows for the manufacture of an ion-selective electrode that is highly selective for calcium. Di-p-octylphenyl phosphate acts as a calcium ionophore, which means it selectively binds to calcium ions and allows them to pass through the membrane. This selectivity is important for accurate measurement of calcium levels in various applications, such as clinical diagnostics or environmental monitoring.Rate this question:
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- 13.
Which one of the following is used both as an internal reference element in potentiometric ion-specific electrodes and as an external reference electrode half-cell of constant potential required to complete a potentiometric cell?
- A.
Calomel
- B.
Mercury vapor
- C.
Silver/silver chloride
- D.
Platinum
Correct Answer
C. Silver/silver chlorideExplanation
Silver/silver chloride is used both as an internal reference element in potentiometric ion-specific electrodes and as an external reference electrode half-cell of constant potential required to complete a potentiometric cell. It provides a stable and reproducible reference potential, making it suitable for use in potentiometric measurements. Calomel, mercury vapor, and platinum are not commonly used as reference electrodes in this context.Rate this question:
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- 14.
Which of the following conditions are among the requirements for a Nernst equilibrium potential to exist for a given charged ion species across a semipermeable membrane, as in an ion-selective electrode?
- A.
The semipermeable membrane must be permeable to many ion species
- B.
A concentration gradient for a given charged ion species must exist across that membrane.
- C.
If a membrane is permeable to two different ion species, then the ion activity of both species can be measured.
- D.
The membrane potential across a semipermeable membrane must be constantly changing.
Correct Answer
B. A concentration gradient for a given charged ion species must exist across that membrane.Explanation
In order for a Nernst equilibrium potential to exist for a given charged ion species across a semipermeable membrane, there must be a concentration gradient for that ion species across the membrane. This means that there must be a difference in the concentration of the ion on either side of the membrane. This concentration gradient is what drives the movement of the ion across the membrane, eventually leading to the establishment of an equilibrium potential. The other conditions mentioned in the question, such as the membrane being permeable to multiple ion species or the membrane potential constantly changing, are not necessary for the existence of a Nernst equilibrium potential.Rate this question:
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- 15.
The reference potential of a silver-silver chloride electrode is determined by the:
- A.
Concentration of potassium chloride filling solution
- B.
Surface area of the electrode
- C.
Activity of total anion in the paste covering electrode
- D.
Concentration of silver in the paste covering electrode
Correct Answer
A. Concentration of potassium chloride filling solutionExplanation
The reference potential of a silver-silver chloride electrode is determined by the concentration of potassium chloride filling solution. This is because the electrode relies on the redox reaction between silver and silver chloride, which is facilitated by the presence of chloride ions. The concentration of potassium chloride in the filling solution affects the concentration of chloride ions available for the reaction, thus influencing the reference potential of the electrode.Rate this question:
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- 16.
What advantage do ion-selective analyzers using undiluted serum samples have over analyzers that use diluted samples?
- A.
They can measure over a wider range of concentration
- B.
They are not subject to pseudohyponatremia caused by high lipids or high proteins
- C.
They do not require temperature equilibration
- D.
They require less maintenance
Correct Answer
B. They are not subject to pseudohyponatremia caused by high lipids or high proteinsExplanation
Ion-selective analyzers using undiluted serum samples have an advantage over analyzers that use diluted samples because they are not subject to pseudohyponatremia caused by high lipids or high proteins. Pseudohyponatremia is a condition where the sodium levels appear lower than they actually are due to interference from substances like lipids or proteins in the sample. By using undiluted samples, the ion-selective analyzers can accurately measure the concentration of ions without being affected by these substances, providing more reliable results.Rate this question:
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- 17.
The ability of an indicator (measuring) electrode to respond to a single species of ion and not any other is referred to as:
- A.
Sensitivity
- B.
Accuracy
- C.
Precision
- D.
Selectivity
Correct Answer
D. SelectivityExplanation
Selectivity refers to the ability of an indicator electrode to respond specifically to a single species of ion and not any other. In other words, it measures the electrode's ability to discriminate between different ions and only respond to the one it is designed for. Sensitivity, on the other hand, refers to the electrode's ability to detect and respond to small changes in concentration, while accuracy and precision refer to the electrode's ability to provide measurements that are close to the true value and consistent, respectively.Rate this question:
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- 18.
Of the following half cell reactions, identify the oxidation reactions:
- A.
Cu2+ + 2 e- ----> Cu
- B.
2H+ + 2 e- ----> H2
- C.
Al ----> Al3+ + 3e-
- D.
Zn ---> Zn 2+ + 2e-
- E.
Only a and b
- F.
Only c and d
Correct Answer
F. Only c and dExplanation
In the provided half-cell reactions, oxidation involves the loss of electrons, while reduction involves the gain of electrons. Among the given reactions, aluminum (Al) losing electrons to form aluminum ions (Al³⁺) and zinc (Zn) losing electrons to form zinc ions (Zn²⁺) are examples of oxidation.Rate this question:
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- 19.
What is the correct order of migration towards the anode of the following proteins in serum protein electrophoresis: fibrinogen, albumin, IgD, transferrin, haptoglobin?
- A.
Fibrinogen, IgD, Haptoglobin, Transferrin, Albumin
- B.
Fibrinogen, IgD, Transferrin, Haptoglobin, Albumin
- C.
IgD, Fibrinogen, Transferrin, Haptoglobin, Albumin
Correct Answer
C. IgD, Fibrinogen, Transferrin, Haptoglobin, AlbuminExplanation
In serum protein electrophoresis, proteins migrate towards the anode based on their charge and size. IgD, being the smallest protein, migrates the fastest towards the anode. Fibrinogen, being larger than IgD, migrates next. Transferrin, being smaller than Haptoglobin and Albumin, migrates before them. Haptoglobin, being larger than Transferrin and Albumin, migrates before Albumin. Therefore, the correct order of migration towards the anode is IgD, Fibrinogen, Transferrin, Haptoglobin, Albumin.Rate this question:
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- 20.
Immunofixation electrophoresis
- A.
Combines the techniques of zone electrophoresis, isotachophoresis, isoelectric focusing, and gel electrophoresis in small-bore fused silica capillary tubes.
- B.
Involves exposure of electrophoresed proteins to antisera against different immunoglobulin heavy and light chains with resultant precipitation.
- C.
Involves transfer of separated proteins to a strip of nitrocellulose by electroblotting followed by an immunochemical reaction with a specific antibody.
- D.
Uses electrophoresis in two dimensions to assess global changes in protein expression.
Correct Answer
B. Involves exposure of electropHoresed proteins to antisera against different immunoglobulin heavy and light chains with resultant precipitation.Explanation
Immunofixation electrophoresis involves exposing electrophoresed proteins to antisera against different immunoglobulin heavy and light chains, which leads to the precipitation of the proteins. This technique helps in identifying and characterizing specific immunoglobulins present in a sample. By observing the resulting precipitation pattern, it is possible to determine the presence and quantity of different immunoglobulins, which can be useful in diagnosing and monitoring various diseases, such as multiple myeloma and other plasma cell disorders.Rate this question:
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- 21.
On a serum protein electrophoresis, if the albumin band appears distorted and large, the likely cause is:
- A.
PH of electrophoretic buffer incorrect
- B.
Instrument not connected
- C.
Sample overload
- D.
Inappropriate support material used
Correct Answer
C. Sample overloadExplanation
The likely cause for the distorted and large appearance of the albumin band on a serum protein electrophoresis is sample overload. This means that too much of the sample was loaded onto the gel, causing overcrowding and smearing of the bands.Rate this question:
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- 22.
If an electrophoretic buffer were diluted before use instead of using it at normal strength, how would electrophoresis be affected?
- A.
Increased migration rate of protein
- B.
Decreased migration rate of protein
- C.
No change in the rate of migration of protein
- D.
None of the above
Correct Answer
A. Increased migration rate of proteinExplanation
When an electrophoretic buffer is diluted before use, it means that the concentration of ions in the buffer is reduced. This would result in a decrease in the electrical resistance of the buffer. As a consequence, the electric field strength would increase, leading to an increased migration rate of proteins during electrophoresis. Therefore, the correct answer is "Increased migration rate of protein".Rate this question:
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- 23.
Upon receiving a serum sample for protein electrophoresis, which you perform using agarose gel, you note that the specimen is hemolyzed. How would hemolysis affect the banding pattern of this type of electrophoresis?
- A.
There would be an increased alpha1-globulin band
- B.
There would be a decreased beta-globulin band
- C.
There would be an increase in the gamma globulin bands
- D.
A decreased alpha2-globulin band
Correct Answer
D. A decreased alpHa2-globulin bandExplanation
Hemolysis refers to the breakdown of red blood cells, resulting in the release of their contents into the surrounding fluid. In protein electrophoresis using agarose gel, the different protein fractions are separated based on their size and charge. Hemolysis can affect the banding pattern by causing a decrease in the alpha2-globulin band. This is because hemolysis leads to the release of hemoglobin, which is a protein that primarily falls within the alpha2-globulin fraction. Therefore, the presence of hemoglobin in the specimen would result in a decrease in the alpha2-globulin band.Rate this question:
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- 24.
How does the net charge of the proteins in a sample affect the electrophoretic mobility of protein fractions?
- A.
It is inversely proportional to electrophoretic mobility
- B.
It is directly proportional to electrophoretic mobility
- C.
It is equal to the electrophoretic mobility
- D.
There is no relationship between net charge and electrophoretic mobility
Correct Answer
B. It is directly proportional to electropHoretic mobilityExplanation
The correct answer states that the net charge of the proteins in a sample is directly proportional to electrophoretic mobility. This means that as the charge of the proteins increases, their mobility during electrophoresis also increases. This relationship makes sense because proteins with higher charges will experience stronger attractions or repulsions from the electric field, causing them to move faster or slower, respectively. Therefore, the more charged a protein is, the greater its electrophoretic mobility will be.Rate this question:
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- 25.
What would the concentration of albumin be if the total protein value was 85 g/dL and the densitometer measured the albumin fraction to be 55% of the total, what is the albumin concentration?
- A.
Albumin values cannot be calculated using densitometry
- B.
15.4 g/dL
- C.
0.65 g/dL
- D.
46.8 g/dL
Correct Answer
D. 46.8 g/dLExplanation
The total protein concentration in the sample is 85 g/dL, and 55% of this value represents the albumin concentration. 55% of 85 g/dL is 46.8 g/dL.Rate this question:
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- 26.
If viscosity of the support medium used in a protein electrophoresis system is too high (thick), the migration will:
- A.
Increase
- B.
Decrease
- C.
Not be affected
- D.
Nothing
- E.
Nothing
Correct Answer
B. DecreaseExplanation
If the viscosity of the support medium used in a protein electrophoresis system is too high, it means that the medium is thick and resistant to flow. In this case, the migration of proteins through the medium will be hindered and slowed down, resulting in a decrease in migration. Therefore, the correct answer is decrease.Rate this question:
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- 27.
Electrophoretic buffer pH: 8.6 Protein A: isoelectric pH: 7.2 Protein B: isoelectric pH: 5.1 Protein C: isoelectric pH: 8.6 In order of mobility of proteins A,B,C (slowest to fastest) toward the anode will be?
- A.
A, B, C
- B.
B, C, A
- C.
C, A, B
- D.
B, A, C
- E.
C, B, A
Correct Answer
C. C, A, BExplanation
Proteins migrate in an electric field based on their charge. The anode is positively charged, so proteins with a negative charge will migrate towards it. In this case, Protein C has an isoelectric pH of 8.6, which is higher than the electrophoretic buffer pH of 8.6. This means that Protein C will have a negative charge and will migrate towards the anode. Protein A has an isoelectric pH of 7.2, which is lower than the buffer pH, so it will have a positive charge and migrate towards the cathode. Protein B has an isoelectric pH of 5.1, which is also lower than the buffer pH, so it will have a positive charge and migrate towards the cathode as well. Therefore, the correct order of mobility from slowest to fastest towards the anode is C, A, B.Rate this question:
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- 28.
One mole per kilogram of H2O of any solute will cause all of the following except:
- A.
Lower freezing point by 1.86 C
- B.
Raise vapor pressure by 0.3 mmHg
- C.
Raise the boiling point by 0.52 C
- D.
Raise osmotic pressure by 22.4 atm
Correct Answer
B. Raise vapor pressure by 0.3 mmHgExplanation
When a solute is added to a solvent, it lowers the freezing point, raises the boiling point, and raises the osmotic pressure of the solution. However, it does not raise the vapor pressure. In fact, adding a solute to a solvent lowers the vapor pressure of the solution compared to the pure solvent. This is known as Raoult's Law. Therefore, the correct answer is "Raise vapor pressure by 0.3 mmHg."Rate this question:
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- 29.
The freezing point osmometer differs from the vapor pressure osmometer in that the freezing point osmometer only:
- A.
Cools the sample
- B.
Requires a thermoelectric module
- C.
Is sensitive to ethanol
- D.
Requires calibrations with aqueous standards
Correct Answer
C. Is sensitive to ethanolExplanation
The freezing point osmometer differs from the vapor pressure osmometer in that it is sensitive to ethanol. This means that the freezing point osmometer can accurately measure the osmolality of a solution containing ethanol, whereas the vapor pressure osmometer may not be able to do so. The other options mentioned in the question (cooling the sample, requiring a thermoelectric module, and requiring calibrations with aqueous standards) are not specific to the freezing point osmometer and may apply to both types of osmometers.Rate this question:
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- 30.
The observed freezing point of an aqueous solution is -0.93. What is the molality of the solution?
- A.
930
- B.
750
- C.
500
- D.
250
Correct Answer
C. 500Explanation
The observed freezing point of an aqueous solution is directly related to its molality. In this case, the observed freezing point is -0.93, which means that the molality of the solution is 500.Rate this question:
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- 31.
One osmol of a substance is equal to:
- A.
The gram molecular weight divided by the number of particles or ions into which the substance dissociates in solution.
- B.
The gram molecular weight divided by valence
- C.
The weight divided by the gram molecular weight
- D.
The weight divided by the equivalent weight
Correct Answer
A. The gram molecular weight divided by the number of particles or ions into which the substance dissociates in solution.Explanation
One osmol of a substance is equal to the gram molecular weight divided by the number of particles or ions into which the substance dissociates in solution. This is because an osmol is a unit of measurement for the number of particles or ions in a solution, and it is defined as the amount of a substance that will react with or be replaced by one mole of electrons during a chemical reaction. Therefore, to calculate the number of osmoles, we need to divide the gram molecular weight by the number of particles or ions.Rate this question:
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- 32.
What is the weight of 1 osmol of NaCl (Mol weight of NaCl = 58.5g)?
- A.
58.5
- B.
117
- C.
29
- D.
35.5
Correct Answer
C. 29Explanation
The weight of 1 osmol of NaCl is 29 grams.Rate this question:
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- 33.
Ion selective electrodes measure potential difference across a membrane using the principles of
- A.
Coulometry.
- B.
Potentiometry.
- C.
Amperometry.
- D.
Conductivity.
Correct Answer
B. Potentiometry.Explanation
Potentiometry is the correct answer because ion selective electrodes measure the potential difference across a membrane. Potentiometry is a technique that measures the potential difference between two electrodes, which in this case are the ion selective electrode and a reference electrode. This potential difference is proportional to the concentration of the specific ion being measured. Coulometry measures the quantity of electricity transferred during an electrochemical reaction, amperometry measures the current flowing in an electrochemical cell, and conductivity measures the ability of a solution to conduct an electric current.Rate this question:
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- 34.
The type of electrode that represents the potential changes in an ion species that is present in the solution in which it is immersed is the _____ electrode.
- A.
Reference
- B.
Indicator
- C.
Gas sensing
- D.
Polymer
Correct Answer
B. IndicatorExplanation
An indicator electrode is a type of electrode that represents the potential changes in an ion species that is present in the solution in which it is immersed. This electrode is used to determine the concentration of a specific ion in a solution by measuring the potential difference between the indicator electrode and a reference electrode. It is commonly used in analytical chemistry to monitor pH levels or to detect the presence of certain ions in a solution.Rate this question:
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- 35.
An electrochemical technique used to measure chloride in serum or plasma is
- A.
A Guthrie test.
- B.
Amperometry.
- C.
Coulometry.
- D.
Voltammetry.
Correct Answer
C. Coulometry.Explanation
Coulometry is an electrochemical technique that is used to measure the concentration of chloride in serum or plasma. It works by passing a known electric current through the sample and measuring the amount of charge required to oxidize the chloride ions present. This method is highly accurate and precise, making it a commonly used technique in clinical laboratories for measuring chloride levels. The Guthrie test is a different test used for detecting phenylketonuria, and amperometry and voltammetry are also electrochemical techniques but are not specifically used for measuring chloride levels.Rate this question:
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- 36.
The measurement of the voltage difference between two half-cells immersed in solution is referred to as
- A.
Coulometry.
- B.
Turbidimetry.
- C.
Potentiometry.
- D.
Amperometry.
Correct Answer
C. Potentiometry.Explanation
Potentiometry is the measurement of the voltage difference between two half-cells immersed in a solution. It is a technique used to determine the concentration or activity of ions in a solution by measuring the potential difference between an indicator electrode and a reference electrode. This method is commonly used in analytical chemistry to study electrochemical reactions and determine the equilibrium constants of redox reactions.Rate this question:
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- 37.
The technique used to determine the absolute amount of electroactive substance by measuring the amount of current passing between two electrodes in an electrochemical cell during a titration reaction is referred to as
- A.
Amperometry
- B.
Coulometry
- C.
Potentiometry
- D.
Turbidimetry
Correct Answer
B. CoulometryExplanation
Coulometry is the technique used to determine the absolute amount of electroactive substance by measuring the amount of current passing between two electrodes in an electrochemical cell during a titration reaction. It involves the quantitative measurement of electric charge and is often used in the analysis of metals and other electroactive substances. Amperometry measures the current at a constant potential, potentiometry measures the potential difference between two electrodes, and turbidimetry measures the scattering of light to determine the concentration of particles in a solution.Rate this question:
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- 38.
A commonly used glass electrode that is used as a reference electrode in pH measurements is the _____ electrode.
- A.
Calomel
- B.
Mercury Vapor
- C.
Silver/Silver Chloride
- D.
Platinum
Correct Answer
A. CalomelExplanation
The correct answer is Calomel. Calomel is commonly used as a reference electrode in pH measurements because it has a stable and reproducible potential. It consists of a mercury-based electrode with a calomel paste that acts as a reference electrolyte. The calomel electrode is widely used in various industries and scientific research due to its reliability and accuracy in pH measurements.Rate this question:
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- 39.
A PCO2 electrode:
- A.
Uses coulometric titration to measure the absolute level of CO2 in blood through the combination of CO2 with water.
- B.
Is a potentiometric cell in which carbon dioxide gas from the sample diffuses through a membrane and forms carbonic acid
- C.
Measures the ability of carbonate ions in solution to carry current under the influence of a potential difference
- D.
Uses a gas-permeable membrane to detect CO2 with very high selectivity over other easily reduced species that might be present in a given sample.
Correct Answer
B. Is a potentiometric cell in which carbon dioxide gas from the sample diffuses through a membrane and forms carbonic acidExplanation
A PCO2 electrode is a potentiometric cell in which carbon dioxide gas from the sample diffuses through a membrane and forms carbonic acid. Potentiometric cells measure the potential difference between two electrodes, in this case, the PCO2 electrode and a reference electrode, to determine the concentration of a specific ion or gas. In this case, the PCO2 electrode measures the concentration of carbon dioxide in a sample by allowing the gas to diffuse through a membrane and react with water to form carbonic acid. The potential difference generated by this reaction is then measured to determine the concentration of CO2.Rate this question:
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- 40.
Incorporation of _____, a neutral antibiotic, into a polyvinyl chloride membrane allows for the manufacture of an ion-selective electrode that is highly selective for potassium.
- A.
Tetracycline
- B.
Nonactin
- C.
Valinomycin
- D.
Erythromycin
Correct Answer
C. ValinomycinExplanation
Valinomycin is a neutral antibiotic that has a high affinity for potassium ions. When incorporated into a polyvinyl chloride membrane, it allows for the manufacture of an ion-selective electrode that is highly selective for potassium. This means that the electrode will primarily detect and measure potassium ions in a solution, making it useful for potassium ion analysis in various applications.Rate this question:
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- 41.
The type of ion-selective electrode mentioned in the preceding question is in a category of electrodes referred to as _____ electrodes.
- A.
Glass
- B.
Inert metal
- C.
Polymer membrane
- D.
Participating metal
Correct Answer
C. Polymer membraneExplanation
The correct answer is "Polymer membrane". This type of ion-selective electrode uses a polymer membrane as the sensing element. The polymer membrane is designed to selectively allow certain ions to pass through, while blocking others. This allows the electrode to measure the concentration of specific ions in a solution. Polymer membrane electrodes are commonly used in various applications, including environmental monitoring, medical diagnostics, and industrial processes.Rate this question:
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Mar 26, 2024Quiz Edited by
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Expert Reviewed by
Zohra Sattar Waxali -
Dec 07, 2012Quiz Created by
J1_black
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