MCQ on Electrochemical Methods of Analysis

1. What is the fundamental principle of conductometry in analytical chemistry?

• A) Measurement of electrical resistance
• B) Measurement of voltage
• C) Measurement of temperature
• D) Measurement of pressure

Correct Answer: A) Measurement of electrical resistance.

2. In conductometry, what is the unit of measurement for electrical conductivity?

• A) Ohms (Ω)
• B) Volts (V)
• C) Siemens per meter (S/m)
• D) Hertz (Hz)

Correct Answer: C) Siemens per meter (S/m).

3.What is the primary purpose of a conductivity cell in conductometric measurements?

• A) To measure voltage
• B) To generate electrical resistance
• C) To measure electrical conductivity
• D) To generate electrical potential

Correct Answer: C) To measure electrical conductivity.

4.Conductometric titrations are commonly used in analytical chemistry. What is the typical property that changes during a conductometric titration?

• A) Temperature
• B) pH
• C) Electrical conductivity
• D) Optical density

Correct Answer: C) Electrical conductivity.

5.In conductometry, what type of ions conduct electrical current in solution?

• A) Anions
• B) Cations
• C) Neutrons
• D) Electrons

Correct Answer: B) Cations.

6.What is the primary function of a reference Electrode in potentiometry?

• A) To measure electrical conductivity
• B) To measure voltage
• C) To maintain a constant potential
• D) To generate electrical resistance

Correct Answer: C) To maintain a constant potential.

7.In potentiometric titrations, what is the role of the indicator electrode?

• A) To maintain a constant potential
• B) To measure electrical conductivity
• C) To generate electrical resistance
• D) To sense changes in potential

Correct Answer: D) To sense changes in potential.

8.The Standard Hydrogen Electrode (SHE) is commonly used as a reference electrode. What is the electrode potential of the SHE under standard conditions?

• A) -1.23 V
• B) 0 V
• C) +1.23 V
• D) +0.0592 V

Correct Answer: B) 0 V.

9.Which electrode is typically used as the reference electrode in potentiometric measurements?

• A) Glass electrode
• B) Metal electrode
• C) Silver chloride electrode
• D) Calomel electrode

Correct Answer: D) Calomel electrode.

10.What is the purpose of a salt bridge in a potentiometric cell?

• A) To conduct electricity
• B) To maintain a constant potential
• C) To generate electrical resistance
• D) To measure electrical conductivity

Correct Answer: B) To maintain a constant potential.

11.What is the fundamental principle of polarography in electrochemical analysis?

• A) Measurement of voltage
• B) Measurement of electrical resistance
• C) Measurement of current as a function of voltage
• D) Measurement of temperature

Correct Answer: C) Measurement of current as a function of voltage.

12.What equation, developed by Ilkovic, is commonly used in polarography to describe the relationship between current and voltage?

• A) Ohm’s law
• B) Nernst equation
• C) Faraday’s law
• D) Ilkovic equation

Correct Answer: D) Ilkovic equation.

13. In polarography, what is the purpose of the dropping mercury electrode (DME)?

• A) To measure voltage
• B) To maintain a constant potential
• C) To generate electrical resistance
• D) To generate a mercury drop for the electrode

Correct Answer: D) To generate a mercury drop for the electrode.

14. What is the primary application of polarography in analytical chemistry?

• A) Determination of electrical resistance
• B) Determination of pH
• C) Determination of current-voltage relationships
• D) Determination of concentration of electroactive species

Correct Answer: D) Determination of concentration of electroactive species.

15. The rotating platinum electrode is commonly used in polarography. What advantage does it offer compared to other electrodes?

• A) It is less expensive.
• B) It is easier to maintain.
• C) It provides a larger surface area for measurements.
• D) It does not require a reference electrode.

Correct Answer: C) It provides a larger surface area for measurements.

In conductometric titrations, what property of a solution is typically monitored as the titration progresses?

• A) Color intensity
• B) pH value
• C) Electrical conductivity
• D) Refractive index

Correct Answer: C) Electrical conductivity.

Conductometry is commonly used to determine the concentration of ions in solution. What happens to the electrical conductivity as the ion concentration increases?

• A) It decreases
• B) It remains constant
• C) It increases
• D) It fluctuates randomly

Correct Answer: C) It increases.

Which type of solution would be expected to have higher electrical conductivity: a strong electrolyte solution or a weak electrolyte solution?

• A) Strong electrolyte solution
• B) Weak electrolyte solution
• C) Both have the same conductivity
• D) It depends on the temperature

Correct Answer: A) Strong electrolyte solution.

How is the electrical conductivity of a solution related to the concentration of ions?

• A) It is inversely proportional to ion concentration.
• B) It is directly proportional to ion concentration.
• C) It is unrelated to ion concentration.
• D) It is exponentially related to ion concentration.

Correct Answer: B) It is directly proportional to ion concentration.

What is the typical shape of a conductometric titration curve when plotting electrical conductivity against the volume of titrant added?

• A) Linear
• B) Parabolic
• C) Sigmoidal
• D) Exponential

Correct Answer: C) Sigmoidal.

In potentiometry, which electrode is commonly used as the reference electrode for pH measurements?

• A) Glass electrode
• B) Metal electrode
• C) Silver chloride electrode
• D) Standard hydrogen electrode

Correct Answer: A) Glass electrode.

How does a glass electrode measure pH?

• A) By generating a voltage proportional to pH
• B) By conducting electrical current through the solution
• C) By measuring the temperature of the solution
• D) By emitting light at a wavelength corresponding to pH

Correct Answer: A) By generating a voltage proportional to pH.

What is the function of the reference electrode in potentiometry?

• A) To measure pH
• B) To maintain a constant potential
• C) To generate electrical resistance
• D) To emit light for measurements

Correct Answer: B) To maintain a constant potential.

When performing a potentiometric titration, what is the endpoint of the titration determined by?

• A) A color change of the indicator
• B) The measurement of electrical conductivity
• C) A sudden change in potential
• D) The formation of a precipitate

Correct Answer: C) A sudden change in potential.

Potentiometry is often used to measure the concentration of ions in solution. Which of the following ions is commonly measured using this technique?

• A) Nitrate (NO₃⁻)
• B) Hydroxide (OH⁻)
• C) Sodium (Na⁺)
• D) Carbonate (CO₃²⁻)

Correct Answer: B) Hydroxide (OH⁻).

What is the primary advantage of using a mercury drop electrode (DME) in polarography?

• A) It requires less maintenance.
• B) It provides a larger surface area for measurements.
• C) It does not require a reference electrode.
• D) It is less expensive.

Correct Answer: B) It provides a larger surface area for measurements.

In polarography, what is the primary role of the indicator electrode?

• A) To measure voltage
• B) To maintain a constant potential
• C) To generate electrical resistance
• D) To sense changes in current

Correct Answer: D) To sense changes in current.

The Ilkovic equation is commonly used in polarography. What parameter does this equation describe?

• A) Current-voltage relationship
• B) pH measurement
• C) Temperature effect on potential
• D) Relationship between drop size and current

Correct Answer: A) Current-voltage relationship.

In polarography, the dropping mercury electrode (DME) is used to generate a mercury drop for measurements. What property of mercury makes it suitable for this purpose?

• A) High electrical conductivity
• B) Low vapor pressure
• C) Low toxicity
• D) High density

Correct Answer: B) Low vapor pressure.

What is the purpose of using a calomel electrode as a reference electrode in potentiometry?

• A) To measure the temperature of the solution
• B) To maintain a constant potential
• C) To generate electrical resistance
• D) To emit light for measurements

Correct Answer: B) To maintain a constant potential.

When using a silver chloride electrode as a reference electrode in potentiometry, what is its primary advantage?

• A) It is inexpensive and readily available.
• B) It provides a large surface area for measurements.
• C) It is resistant to corrosion.
• D) It measures electrical resistance accurately.

Correct Answer: A) It is inexpensive and readily available.

In a potentiometric titration, how is the endpoint of the titration typically detected?

• A) By measuring the change in temperature
• B) By noting a change in color of the indicator
• C) By monitoring a sudden change in potential
• D) By recording the formation of a precipitate

Correct Answer: C) By monitoring a sudden change in potential.

Potentiometry is often employed to determine the concentration of various ions in solution. Which of the following ions is commonly measured using a silver-silver chloride electrode?

• A) Sodium (Na⁺)
• B) Hydrogen (H⁺)
• C) Chloride (Cl⁻)
• D) Carbonate (CO₃²⁻)

Correct Answer: C) Chloride (Cl⁻).

What is the key advantage of using a glass electrode in potentiometric measurements for pH determination?

• A) It provides a high electrical conductivity.
• B) It is highly resistant to breakage.
• C) It can be used in a wide range of temperatures.
• D) It generates a voltage proportional to pH.

Correct Answer: D) It generates a voltage proportional to pH.

In polarography, what is the primary role of the dropping mercury electrode (DME)?

• A) To measure voltage
• B) To maintain a constant potential
• C) To generate electrical resistance
• D) To generate a mercury drop for measurements

Correct Answer: D) To generate a mercury drop for measurements.

What is the primary advantage of using a rotating platinum electrode in polarography?

• A) It is less expensive than other electrodes.
• B) It requires minimal maintenance.
• C) It provides a larger surface area for measurements.
• D) It does not require a reference electrode.

Correct Answer: C) It provides a larger surface area for measurements.

• In polarography, what does the Ilkovic equation describe?

• A) The relationship between drop size and current
• B) The temperature effect on potential
• C) The pH measurement method
• D) The current-voltage relationship

Correct Answer: D) The current-voltage relationship.

Polarography is commonly used to determine the concentration of electroactive species in a solution. Which of the following is NOT an electroactive species?

• A) Oxygen (O₂)
• B) Chloride ions (Cl⁻)
• C) Sodium ions (Na⁺)
• D) Hydroxide ions (OH⁻)

Correct Answer: D) Hydroxide ions (OH⁻).

In polarography, what happens to the current as the applied voltage is increased beyond a certain point in a polarogram?

• A) It decreases linearly.
• B) It remains constant.
• C) It increases exponentially.
• D) It abruptly drops to zero.

Correct Answer: D) It abruptly drops to zero.

Polarography (Continued):

In polarography, what is the primary role of the auxiliary electrode, typically made of platinum?

• A) To generate a voltage proportional to pH
• B) To provide a reference potential
• C) To create a stable potential difference
• D) To stir the solution

Correct Answer: C) To create a stable potential difference.

The current in polarography is measured as a function of what parameter?

• A) Time
• B) Temperature
• C) Voltage
• D) Concentration

Correct Answer: C) Voltage.

What is the primary function of the dropping mercury electrode (DME) in polarography?

• A) To measure voltage
• B) To maintain a constant potential
• C) To generate electrical resistance
• D) To facilitate the formation of mercury drops

Correct Answer: D) To facilitate the formation of mercury drops.

Polarography is often used for the determination of trace metal ions in solution. Which metal ion is commonly measured using polarographic techniques?

• A) Sodium (Na⁺)
• B) Potassium (K⁺)
• C) Copper (Cu²⁺)
• D) Calcium (Ca²⁺)

Correct Answer: C) Copper (Cu²⁺).

What is the term for the graphical representation of current versus applied voltage in polarography?

• A) Polarogram
• B) Voltamogram
• C) Amperogram
• D) Conductogram

Correct Answer: A) Polarogram.

Polarographic techniques often involve the use of a mercury electrode. Why is mercury commonly used in these electrodes?

• A) It is a good conductor of electricity.
• B) It has a high melting point.
• C) It is chemically inert.
• D) It is inexpensive.

Correct Answer: C) It is chemically inert.

What is the term for the voltage at which a species undergoing reduction or oxidation in polarography begins to generate a measurable current?

• A) Half-wave potential
• B) Threshold potential
• C) Equivalence potential
• D) Saturation potential

Correct Answer: B) Threshold potential.

Polarography is often employed for the determination of oxygen concentration in various samples. What type of electrode is typically used for this purpose?

• A) Glass electrode
• B) Platinum electrode
• C) Silver electrode
• D) Clark electrode

Correct Answer: D) Clark electrode.

The application of polarography is not limited to quantitative analysis. What other type of information can be obtained from polarograms?

• A) pH of the solution
• B) Concentration of electrolytes
• C) Reaction kinetics
• D) Refractive index

Correct Answer: C) Reaction kinetics.

What is the primary advantage of polarography over other electrochemical methods in terms of sensitivity?

• A) It is less sensitive.
• B) It is equally sensitive.
• C) It is moderately sensitive.
• D) It is highly sensitive.

Correct Answer: D) It is highly sensitive.

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