Case: An electrochemical cell consists of two half-cells connected by a salt bridge. Each half-cell contains a metal immersed in a solution of its salt. The electrode potential is a measure of the tendency of a metal to lose electrons (oxidation) or gain electrons (reduction). The Nernst equation relates the cell potential to the concentration of ions in solution. The Nernst equation helps in calculating the potential of an electrochemical cell under non-standard conditions. The cell potential is affected by temperature, concentration, and the nature of the electrodes.
For a given electrochemical reaction:
where is the cell potential, is the standard electrode potential, is the number of electrons involved, and the concentrations of the products and reactants are taken in molarity.
Questions:
The Nernst equation is used to calculate:
In the Nernst equation, what does the term represent?
The standard electrode potential of a half-cell is determined under:
The cell potential for a reaction decreases when:
Case: Conductivity is a measure of the ability of a solution to conduct electricity, and it depends on the concentration of ions in the solution. The cell constant is a factor that relates the conductance of a solution to the physical dimensions of the cell. Molar conductivity is the conductance of a solution containing one mole of electrolyte. Molar conductivity increases with dilution because the ions in a solution become more dispersed, leading to less ion-ion interaction.
For an electrolyte solution, the relationship between conductivity (κ), molar conductivity (Λ), and concentration (C) is given by:
At infinite dilution, the molar conductivity is called the limiting molar conductivity ( ).
Questions:
The molar conductivity of an electrolyte solution is:
The cell constant of a conductivity cell is:
The conductivity of a solution is directly related to:
At infinite dilution, the molar conductivity of an electrolyte is:
Case: An electrolytic cell is a type of electrochemical cell where electrical energy is used to drive a non-spontaneous chemical reaction. This process is known as electrolysis. Faraday’s laws of electrolysis quantify the relationship between the amount of substance deposited or liberated during electrolysis and the quantity of electric charge passed through the cell. Faraday’s first law states that the amount of substance deposited is directly proportional to the quantity of charge. Faraday’s second law states that the amount of different substances deposited or liberated by the same quantity of charge is proportional to their equivalent weights.
Questions:
Faraday’s first law of electrolysis states that the amount of substance deposited at an electrode is directly proportional to:
Which of the following is true according to Faraday’s second law of electrolysis?
In an electrolytic cell, the substance deposited at the cathode is:
The amount of substance deposited during electrolysis depends on:
Case: A galvanic cell (or voltaic cell) is an electrochemical cell that generates electrical energy from spontaneous chemical reactions. In a galvanic cell, two half-cells are connected, each containing a metal electrode immersed in a solution of its ion. The half-reaction at the anode involves oxidation, while the half-reaction at the cathode involves reduction. The potential difference between the two electrodes is called the cell potential. The standard cell potential is calculated using the standard electrode potentials of the half-reactions.
For a spontaneous reaction, the cell potential is positive, and the reaction proceeds in the forward direction. The Nernst equation can be used to calculate the cell potential under non-standard conditions.
Questions:
In a galvanic cell, the anode is where:
The cell potential of a galvanic cell can be calculated by:
A positive cell potential in a galvanic cell indicates:
The salt bridge in a galvanic cell is used to:
Case: Corrosion is the process of deterioration of metals due to electrochemical reactions, often involving oxygen and moisture from the environment. The process of corrosion is an example of an electrochemical cell where the metal undergoes oxidation at the surface, and oxygen undergoes reduction. Rusting of iron is a common example of corrosion. The protection of metals from corrosion involves techniques like galvanization (coating the metal with a layer of zinc), cathodic protection, and painting.
Questions:
Corrosion of iron involves:
Which of the following methods is used to prevent corrosion?
In the process of rusting, iron loses electrons and is oxidized to:
The presence of moisture in the environment accelerates corrosion because: