Electrochemistry: Electrode Potential and Reference Electrodes

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Questions and Answers

What is the primary function of the B-Reference electrode in a pH meter?

To amplify the electrical charge

To adjust the pH meter before taking the reading

To complete the electrical circuit (correct)

To control the temperature

What would happen if the electrodes are not cleaned?

The pH meter would break down

The pH meter would not be affected

The pH meter would be more accurate

The pH meter would be less accurate (correct)

What is the purpose of the Temperature knob in a pH meter?

To control the temperature (correct)

To amplify the electrical charge

To complete the electrical circuit

To adjust the pH meter before taking the reading

In which industry is the pH meter particularly used for dairy products?

Food Signup and view all the answers

Why is it essential to keep the probes moist when not in use?

To prevent them from getting dry Signup and view all the answers

What is an advantage of pH meters?

pH Calibration is low-priced and robust Signup and view all the answers

What is a disadvantage of pH meters?

Heat affects the output readings Signup and view all the answers

What is necessary for the accuracy and precision of the pH meter?

To clean lines of the probes Signup and view all the answers

What is the primary function of a pH meter?

To determine the acidity or alkalinity of a solution Signup and view all the answers

What is the symbol 'P' in pH derived from?

The mathematical symbol for negative logarithm Signup and view all the answers

What is the pH value of a solution with equal concentrations of hydrogen and hydroxyl ions?

Exactly 7 Signup and view all the answers

What is the purpose of the silver wire coated with silver chloride in a glass electrode?

To carry current through the half-cell reaction Signup and view all the answers

What type of pH meter is ideal for laboratory use?

Desktop pH meter Signup and view all the answers

What is the typical measurement range of a pen pH meter?

A conventional range for easy and handy equipment Signup and view all the answers

What is the result of a pH meter measurement displayed in terms of?

The pH value of the solution Signup and view all the answers

What is the pH scale range?

0 to 14 Signup and view all the answers

Study Notes

pH Meter

The electrode potential is constant due to the constant chloride ion concentration (0.1 M).

Reference Electrode (Calomel Electrode)

It is used to complete the electrical circuit.
A common reference electrode is another Ag/AgCl electrode.
The Ag/AgCl electrode is immersed in a 0.1 M KCl solution, making contact with the test solution through a porous fiber.

Components of pH Meter

Electrode holder
Amplifier: amplifies the electrical charge from the electrode and passes it to the galvanometer as readable current.
Galvanometer or Digital display
Temperature knob: controls the temperature.
Adjustment knob: adjusts the pH meter before taking readings.

Advantages of pH Meter

pH calibration is low-priced and robust.
Pocket size pH meters are user-friendly.
Accounts are reliable and specific.
Readings are accurate and precise.

Disadvantages of pH Meter

Heat affects the output readings.
pH calibration using glass electrodes requires cleaning to prevent deposition influencing the readings.

Application of pH Meter

In agriculture industries, it measures the pH of soil.
In municipal water supplies, it measures water quality.
In chemical and pharmaceutical industries, it measures the pH value of solutions.
In the food industry, it is used for dairy products like cheese, curds, and yogurts.

Maintenance of pH Meter

Cleaning lines of the probes is essential for accuracy and precision.
Probes are kept moist when not in use with a medium.
Electrodes should not be allowed to become dry.
Regular calibration of pH meter is essential.

pH Scale

pH is a symbol that describes the degree of acidity or alkalinity.
It is measured on a scale of 0 to 14.
pH is derived from the negative logarithm (P) and the chemical symbol for Hydrogen (H).

pH Value

It is directly related to the ratio of hydrogen ion (H+) and hydroxyl ion (OH-) concentrations.
If H+ concentration is higher than OH- concentration, the material is acidic (pH < 7).
If OH- concentration is higher than H+ concentration, the material is basic (pH > 7).
If H+ concentration is equal to OH- concentration, the material is neutral (pH = 7).

Types of pH Meter

Portable pH meter: covers an extensive range of regularly employed instruments.
Desktop pH meter: ideal for laboratory use.
Pen pH meter: composed of a single scale, conventional measurement range for easy and handy equipment.

Electrode

There are two types of electrodes: glass electrode (measuring electrode) and Ag/AgCl electrode.
The Ag/AgCl electrode carries current through the half-cell reaction.

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Description

This quiz covers the concept of electrode potential in electrochemistry, specifically with regards to the Ag/AgCl electrode and its use as a reference electrode in a KCl solution.