(A) The standard reduction potential of $Fe^{3+}/Fe^{2+}$ is $+0.77 \ V$. In a mixture of $H_{2}SO_{4}$ and $H_{3}PO_{4}$, $Fe^{3+}$ ions react with p

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formation of the species $[FeHPO_{4}]^{+}$

(A) The standard reduction potential of $Fe^{3+}/Fe^{2+}$ is $+0.77 \ V$. In a mixture of $H_{2}SO_{4}$ and $H_{3}PO_{4}$, $Fe^{3+}$ ions react with phosphate ions to form a stable complex, $[FeHPO_{4}]^{+}$. According to the Nernst equation, $E = E^{\circ} - (0.059/n) \log(1/[Fe^{3+}])$. As the concentration of free $Fe^{3+}$ ions decreases due to complex formation, the reduction potential decreases from $+0.77 \ V$ to $+0.61 \ V$.

Class 12 Chemistry Electrochemistry Electrode potential and ECell

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The formal potential of $Fe^{3+}/Fe^{2+}$ in a sulphuric acid and phosphoric acid mixture $(E^{\circ}=+0.61 \ V)$ is much lower than the standard potential $(E^{\circ}=+0.77 \ V)$. This is due to

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A
formation of the species $[FeHPO_{4}]^{+}$
B
lowering of potential upon complexation
C
formation of the species $[FeSO_{4}]^{+}$
D
high acidity of the medium

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Electrochemistry

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Electrode potential and ECell

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For the reactions $Ag^{+} (aq) + e^{-} \rightarrow Ag_{(s)}$ and $Sn^{2+} (aq) + 2e^{-} \rightarrow Sn_{(s)}$,the standard electrode potentials at $25^{\circ}C$ are $0.80 \ V$ and $-0.14 \ V$ respectively. What is the standard $emf$ of the cell $Sn_{(s)} | Sn^{2+}_{(aq)} (1 \ M) || Ag^{+}_{(aq)} (1 \ M) | Ag_{(s)}$ in $volts$?

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$A$ $1.0 \ M$ solution with respect to each of the metal halides $AX_3, BX_2, CX_3$ and $DX_2$ is electrolysed using platinum electrodes. If
$E^o_{A^{3+}/A} = 1.50 \ V, \quad E^o_{B^{2+}/B} = 0.3 \ V,$
$E^o_{C^{3+}/C} = -0.74 \ V, \quad E^o_{D^{2+}/D} = -2.37 \ V.$
The correct sequence in which the various metals are deposited at the cathode is

MediumAIIMS 2014

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Calculate the standard free energy change for the reaction $\frac{1}{2}Cu_{(s)} + \frac{1}{2}Cl_{2(g)} \rightleftharpoons \frac{1}{2}Cu^{2+} + Cl^-$ taking place at $25\ ^oC$ in a cell whose standard e.m.f. is $1.02 \ V$ (in $J$).

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The two half-cell reactions of an electrochemical cell are given as: $Ag^{+} + e^{-} \rightarrow Ag$; $E^{\circ}_{Ag^{+}/Ag} = 0.7995 \ V$ and $Fe^{2+} \rightarrow Fe^{3+} + e^{-}$; $E^{\circ}_{Fe^{3+}/Fe^{2+}} = 0.7710 \ V$. The value of cell $EMF$ will be: (in $V$)

MediumWBJEE 2014

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Based on the given data,which is the strongest oxidizing agent? $E_{Li^+|Li}^o = -3.03 \ V$,$E_{Ba^{2+}|Ba}^o = -2.73 \ V$,$E_{Na^+|Na}^o = -2.71 \ V$,and $E_{Mg^{2+}|Mg}^o = -2.37 \ V$.

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The formal potential of $Fe^{3+}/Fe^{2+}$ in a sulphuric acid and phosphoric acid mixture $(E^{\circ}=+0.61 \ V)$ is much lower than the standard potential $(E^{\circ}=+0.77 \ V)$. This is due to

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Calculate the standard free energy change for the reaction $\frac{1}{2}Cu_{(s)} + \frac{1}{2}Cl_{2(g)} \rightleftharpoons \frac{1}{2}Cu^{2+} + Cl^-$ taking place at $25\ ^oC$ in a cell whose standard e.m.f. is $1.02 \ V$ (in $J$).

The two half-cell reactions of an electrochemical cell are given as: $Ag^{+} + e^{-} \rightarrow Ag$; $E^{\circ}_{Ag^{+}/Ag} = 0.7995 \ V$ and $Fe^{2+} \rightarrow Fe^{3+} + e^{-}$; $E^{\circ}_{Fe^{3+}/Fe^{2+}} = 0.7710 \ V$. The value of cell $EMF$ will be: (in $V$)

Based on the given data,which is the strongest oxidizing agent? $E_{Li^+|Li}^o = -3.03 \ V$,$E_{Ba^{2+}|Ba}^o = -2.73 \ V$,$E_{Na^+|Na}^o = -2.71 \ V$,and $E_{Mg^{2+}|Mg}^o = -2.37 \ V$.

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