Concept explainers
Consider a Daniell cell operating under nonstandard-state conditions. Suppose that the cell’s reaction is multiplied by 2. What effect does this have on each of the following quantities in the Nernst equation: (a) E, (b) E°, (c) Q, (d) ln Q, (e) n?
(a)

Interpretation:
The changes
Concept Introduction:
Nernst equation is one of the important equation in electrochemistry. In Nernst equation the electrode potential of a cell reaction is related to the standard electrode potential, concentration or activities of the species that is involved in the chemical reaction and temperature.
Where,
At room temperature
The standard electrode potential
Answer to Problem 18.118QP
On multiplying the overall cell equation for Daniel cell by a factor of two
Cell potential
Explanation of Solution
To explain the how cell potential
The overall reaction in the Daniel cell is found to be,
Nernst equation for the above reaction is given below,
Lets multiply the overall reaction by two and write the Nernst equation for the new equilibrium.
On multiplying the overall cell equation with two, the total number of electrons transferred becomes twice of the initial number and the equilibrium constant is squared.
Equation number
On simplifying equation
Hence, it is clear that on multiplying the overall cell equation by a factor of two, cell potential remains the same.
(b)

Interpretation:
The changes
Concept Introduction:
Nernst equation is one of the important equation in electrochemistry. In Nernst equation the electrode potential of a cell reaction is related to the standard electrode potential, concentration or activities of the species that is involved in the chemical reaction and temperature.
Where,
At room temperature
The standard electrode potential
Answer to Problem 18.118QP
On multiplying the overall cell equation for Daniel cell by a factor of two
Explanation of Solution
To explain the how
The overall reaction in the Daniel cell is found to be,
Nernst equation for the above reaction is given below,
The standard electrode potential depends only upon the standard reduction potentials of cathode and anode. It is independent upon the stoichiometric coefficients of the reactants and products. Hence, on multiplying the overall equation by two
(c)

Interpretation:
The changes
Concept Introduction:
Nernst equation is one of the important equation in electrochemistry. In Nernst equation the electrode potential of a cell reaction is related to the standard electrode potential, concentration or activities of the species that is involved in the chemical reaction and temperature.
Where,
At room temperature
The standard electrode potential
Answer to Problem 18.118QP
On multiplying the overall cell equation for Daniel cell by a factor of two
The equilibrium constant
Explanation of Solution
To explain the how the equilibrium constant
Explanation:
The overall reaction in the Daniel cell is found to be,
Nernst equation for the above reaction is given below,
The equilibrium constant,
On multiplying the equation by two the equilibrium constant becomes,
On multiplying the overall equation by two, the equilibrium constant is squared.
(d)

Interpretation:
The changes
Concept Introduction:
Nernst equation is one of the important equation in electrochemistry. In Nernst equation the electrode potential of a cell reaction is related to the standard electrode potential, concentration or activities of the species that is involved in the chemical reaction and temperature.
Where,
At room temperature
The standard electrode potential
Answer to Problem 18.118QP
On multiplying the overall cell equation for Daniel cell by a factor of two
The value of
Explanation of Solution
To explain the how
The overall reaction in the Daniel cell is found to be,
Nernst equation for the above reaction is given below,
or
On multiplying the equation by two,
This equation can also represented as,
On multiplying the equation by two, the value of
(e)

Interpretation:
The changes
Concept Introduction:
Nernst equation is one of the important equation in electrochemistry. In Nernst equation the electrode potential of a cell reaction is related to the standard electrode potential, concentration or activities of the species that is involved in the chemical reaction and temperature.
Where,
At room temperature
The standard electrode potential
Answer to Problem 18.118QP
On multiplying the overall cell equation for Daniel cell by a factor of two
The number of electrons
Explanation of Solution
To explain the how number of electrons
The overall reaction in the Daniel cell is found to be,
The half cell reactions are,
On multiplying each half cell equations by two
Hence, it is clear that the number of electrons involved in the given reaction is doubled when the overall reaction is multiplied by a factor of two
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Chapter 18 Solutions
CHEMISTRY 1111 LAB MANUAL >C<
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