Electrochemistry

Question

What is the Nernst equation for the Potential of an electrode? Can Nernst equation be applied to the cell relation ? Apply this equation to a general reaction.
$aA + bB \to cC + dD$

Solution

The concentration of all species involved in the species involved in the electrode reaction is unity.This need not be always true.
Nernst shows that for the electrode reaction:

M^{n +} (aq) + {ne}^{-} \to M (s)

the electrode potential at any concentration measured with respect to standard hydrogen electrode can be represented by:

E_{(\frac{M^{n +}}{M})} = E_{\frac{M^{n +}}{M}}^{-} - \frac{RT}{nF} In \frac{[M]}{[M^{n +}]}

but concentration of solid M is taken as unity as we have

E_{(\frac{M^{n +}}{M})} = E_{\frac{M^{n +}}{M}}^{-} - \frac{RT}{nF} In \frac{[1]}{[M^{n +}]}

R is gas constant (8.314 JK–1 mol–1),
F is Faraday constant (96487 C mol^–1), T is temperature in kelvin and [Mⁿ⁺] is the concentration of the species, Mn

Let us take a electrode reaction

{Zn}^{2 +} + 2 e^{-} \to Zn

The Nernst equation of this electrode

E = E ° - \frac{2.303 RT}{nF} \log \frac{a_{product}}{a_{reactant}}

Instead of activity, we can take molar concentration.

E = E ° - \frac{0.05916}{n} \log \frac{[Zn]}{[{Zn}^{2 +}]}

For pure solid and liquid molar concentration is taken as unity.

E = E ° - \frac{0.05916}{2} \log \frac{1}{[{Zn}^{2 +}]}

Yes, Nernst equation can be applied to the cell reaction.

aA + bB \to cC + dD

E = E ° - \frac{0.05916}{n} \log \frac{{[C]}^{c} {[D]}^{d}}{{[A]}^{a} {[B]}^{b}}

Some More Questions From Electrochemistry Chapter

How would you determine the standard electrode potential of the system Mg²⁺/Mg?

Can you store copper sulphate solutions in a Zinc pot?

Why does the conductivity of a solution decrease with dilution?

Suggest a way to determine the Λ°_m value of water.

The molar conductivity of 0.025 mol L^–1methanoic acid is 46.1 S cm² mol^–1. Calculate its degree of dissociation and dissociation constant. Give λ°(H⁺) = 349.6 S cm²mol^–1 and λ° (HCOO^– ) = 54.6 s cm² mol^–1.

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Electrochemistry

What is the Nernst equation for the Potential of an electrode? Can Nernst equation be applied to the cell relation ? Apply this equation to a general reaction.
$aA + bB \to cC + dD$

Some More Questions From Electrochemistry Chapter

How would you determine the standard electrode potential of the system Mg²⁺/Mg?

Can you store copper sulphate solutions in a Zinc pot?

Why does the conductivity of a solution decrease with dilution?

Suggest a way to determine the Λ°_m value of water.

The molar conductivity of 0.025 mol L^–1methanoic acid is 46.1 S cm² mol^–1. Calculate its degree of dissociation and dissociation constant. Give λ°(H⁺) = 349.6 S cm²mol^–1 and λ° (HCOO^– ) = 54.6 s cm² mol^–1.

If the current of 0.5 ampere flows through a metallic wire for 2 hours, then how many electrons flow through the wire?

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For Daily Free Study Material Join wiredfaculty

Electrochemistry

What is the Nernst equation for the Potential of an electrode? Can Nernst equation be applied to the cell relation ? Apply this equation to a general reaction.aA+bB→cC+dD

Some More Questions From Electrochemistry Chapter

How would you determine the standard electrode potential of the system Mg2+/Mg?

Can you store copper sulphate solutions in a Zinc pot?

Why does the conductivity of a solution decrease with dilution?

Suggest a way to determine the Λ°m value of water.

The molar conductivity of 0.025 mol L–1 methanoic acid is 46.1 S cm2 mol–1. Calculate its degree of dissociation and dissociation constant. Give λ°(H+) = 349.6 S cm2 mol–1 and λ° (HCOO– ) = 54.6 s cm2 mol–1.

If the current of 0.5 ampere flows through a metallic wire for 2 hours, then how many electrons flow through the wire?

Mock Test Series

NCERT Sample Papers

Entrance Exams Preparation

What is the Nernst equation for the Potential of an electrode? Can Nernst equation be applied to the cell relation ? Apply this equation to a general reaction.
$aA + bB \to cC + dD$

How would you determine the standard electrode potential of the system Mg²⁺/Mg?

Suggest a way to determine the Λ°_m value of water.

The molar conductivity of 0.025 mol L^–1methanoic acid is 46.1 S cm² mol^–1. Calculate its degree of dissociation and dissociation constant. Give λ°(H⁺) = 349.6 S cm²mol^–1 and λ° (HCOO^– ) = 54.6 s cm² mol^–1.