Discuss the method to determine the cell potential of any cell when a standard hydrogen electrode is considered as the anode,with a suitable example.

Vedclass pdf generator app on play store
Vedclass iOS app on app store
(N/A) Reduction potential: At $298 \ K$,the $emf$ of a cell constructed by taking the standard hydrogen electrode as the anode (reference half-cell) and the other half-cell as the cathode gives the reduction potential of the other half-cell.
Standard hydrogen electrode half-cell $\mid$ another half-cell
(anode half-cell) $\mid$ (cathode half-cell)
Cell potential $=$ (Reduction potential of other cell) $=$ $emf$ value of the other half-cell.
$(b)$ Explanation with a general example:
$(i)$ If the concentrations of the oxidized and reduced forms of the species in the right-hand half-cell are unity,the cell potential equals the standard electrode potential.
General cell: $Pt \mid H_{2(g)} (1 \ bar) \mid H^+_{(aq)} (1 \ M) \| M^{n+}_{(aq)} (1 \ M) \mid M_{(s)}$
$(ii)$ $E^{\ominus} = (E^{\ominus}_R - E^{\ominus}_L)$:
Where $E^{\ominus}$ is the standard reduction potential of the cell,$E^{\ominus}_R$ is the standard reduction potential of the right-hand electrode,and $E^{\ominus}_L$ is the standard reduction potential of the left-hand electrode.
Since $E^{\ominus}_L = 0.0 \ V$ for the standard hydrogen electrode,$\therefore E^{\ominus} = (E^{\ominus}_R - 0.0) = E^{\ominus}_R$.
$(iii)$ Hydrogen half-cell $\mid$ Copper half-cell:
$Pt \mid H_{2(g)} (1 \ bar) \mid H^+_{(aq)} (1 \ M) \| Cu^{2+}_{(aq)} (1 \ M) \mid Cu_{(s)}$
The measured $emf$ of the cell is $+0.34 \ V$,which is the standard electrode potential for the reaction:
Oxidation (left): $H_{2(g)} \rightarrow 2H^+_{(aq)} + 2e^- \ (E^{\ominus}_L = 0.0 \ V)$
Reduction (right): $Cu^{2+}_{(aq)} + 2e^- \rightarrow Cu_{(s)}$
$\therefore E^{\ominus}_{cell} = (E^{\ominus}_R - E^{\ominus}_L) = 0.34 \ V \implies E^{\ominus}_R = 0.34 \ V$.
Thus,the standard reduction potential for $Cu^{2+} \mid Cu$ is $+0.34 \ V$.

Explore More

Similar Questions

$MX$ is a sparingly soluble salt that follows the given solubility equilibrium at $298 \ K$: $MX_{(s)} \rightleftharpoons M^{+}_{(aq)} + X^{-}_{(aq)}$; $K_{sp} = 10^{-10}$. If the standard reduction potential for $M^{+}_{(aq)} + e^- \rightarrow M_{(s)}$ is $(E^{\ominus}_{M^{+}/M}) = 0.79 \ V$, then the value of the standard reduction potential for the metal/metal insoluble salt electrode $E^{\ominus}_{X^{-}/MX_{(s)}/M}$ is . . . . . . $mV$. (nearest integer) [Given: $\frac{2.303 RT}{F} = 0.059 \ V$]

$MnO_4^- (aq) + 8H^+ (aq) + 5e^- \to Mn^{2+} (aq) + 4H_2O (l)$; $E_1^o = 1.51 \ V$
$MnO_2 (s) + 4H^+ (aq) + 2e^- \to Mn^{2+} (aq) + 2H_2O (l)$; $E_2^o = 1.21 \ V$
$MnO_4^- (aq) + 4H^+ (aq) + 3e^- \to MnO_2 (s) + 2H_2O (l)$; $E_3^o = ?$
Value of $E_3^o$ will be ............ $V$

Which of the following transformations can be carried out by using $HI$ as a reducing agent,under acidic conditions?
[Given: $I_{2(s)} \rightarrow 2I^- ; E^{\circ} = 0.54 \ V$]
$(i)$ $Cu^+ \rightarrow Cu_{(s)} ; E^{\circ} = 0.52 \ V$
$(ii)$ $Cr^{3+} \rightarrow Cr^{2+} ; E^{\circ} = -0.41 \ V$
$(iii)$ $Fe^{3+} \rightarrow Fe^{2+} ; E^{\circ} = 0.77 \ V$
$(iv)$ $Fe^{2+} \rightarrow Fe_{(s)} ; E^{\circ} = -0.44 \ V$

When does a cell reaction occur spontaneously?

The $E^{0}_{Red}$ values for $P, Q, R$ and $S$ are $-2.90 \, V, +0.34 \, V, +1.20 \, V$ and $-0.76 \, V$ respectively. The decreasing order of their reactivity is:

Vedclass Products

For Students

Vedclass Test Series

Mock tests in real JEE/NEET style with performance analysis. 5-day free trial.

Start Free Trial
For Teachers

Exam Paper Generator

Generate Set A/B/C/D exam papers from 7.5L+ questions in 2 minutes. 3 chapters free.

Try Free
For Institutes

Online Exam Module

Live online exams with unlimited students, 360° analytics & white-label branding.

See Demo