Consider the reaction- 2Ag- - Cd - 2Ag - Cd2-The standard electrode potentials for Ag- Ag and Cd2- Cd couples are 0-80 volt and -0-40 volt respectively-i What is the standard potential E- for this reaction-ii For the electrochemical cell- in which this reaction takes place which electrode is negative electrode-

(i) The half reactions are: 2Ag^+ + Reduction (Cathode)2e^ → Ag , E_Ag^+/ Ag^∘ = 0.80 volt (Reduction potential) Cd →(Anode)OxidationCd^2+ + 2e^ , ...

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Standard XII

Chemistry

SHE

Consider the ...

Question

Consider the reaction,
$2 A g^{+} + C d \to 2 A g + C d^{2 +}$
The standard electrode potentials for $A g^{+} \to A g$ and $C d^{2 +} \to C d$ couples are $0.80 v o l t$ and $- 0.40 v o l t$ respectively.
(i) What is the standard potential $E^{\circ}$ for this reaction?
(ii) For the electrochemical cell, in which this reaction takes place which electrode is negative electrode?

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Solution

(i) The half reactions are:
$2 A g^{+} + 2 e^{-} R e d u c t i o n (C a t h o d e) \to A g$ ,
$E_{A g^{+} / A g}^{\circ} = 0.80 v o l t$ (Reduction potential)
$C d \to C d^{2 +} O x i d a t i o n (A n o d e) + 2 e^{-}$ ,
$E_{C d^{2 +} / C d}^{\circ} = - 0.40 v o l t$ (Reduction potential)
or $E_{C d / C d^{2 +}}^{\circ} = + 0.40 v o l t$
$E^{\circ} = E_{C d / C d^{2 +}}^{\circ} + E_{A g^{+} / A g}^{\circ} = 0.40 + 0.80 = 1.20 v o l t$
(ii) The negative electrode is always the electrode whose reduction potential has smaller value or the electrode where oxidation occurs. Thus, $C d$ electrode is the negative electrode.

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Similar questions

Q. Assertion :If standard reduction potential for the reaction,

A g^{+} + e^{-} \to A g

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2 {A g}^{+} + C d \to 2 A g + {C d}^{2 +}

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Q. Assertion :If standard reduction potential for the reaction

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Q. The standard e.m.f. of the cell involving the reaction,

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Q. The standard electrode potentials for the reactions

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