Electrode Potential and Standard Electrode Potential

IMPORTANT

Electrode Potential and Standard Electrode Potential: Overview

This topic covers concepts, such as, Electrode Potential, Factors Affecting Electrode Potential of an Electrode/EMF of a cell, Standard Hydrogen Electrode & Calomel Electrode etc.

Important Questions on Electrode Potential and Standard Electrode Potential

MEDIUM
IMPORTANT

Two half-reactions of an electrochemical cell are given below :

 MnO4(aq)+8H+(aq)+5eMn2+(aq)+4H2O(l), E°=+1.51V

 Sn2+(aq)Sn4+(aq)+2e,E°=+0.15V

What is the standard cell potential?

EASY
IMPORTANT

Two half-cell reactions of an electrochemical cell are given below :

 MnO4(aq)+8H+(aq)+5eMn2+(aq)+4​ H2O(l),E°=1.51V

 Sn2+(aq)Sn4+(aq)+2eE°=+0.15V

What would be the final cell potential?

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A copper-silver cell is set up. The copper ion concentration in it is 0.10 M. The concentration of silver ion is not known. The cell potential measured is 0.422 V. Determine the concentration of silver ion in the cell. Given :  EAg+/Ago=+0.80 V, ​ ECu2+/Cuo=+0.34​ V.

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An acidic solution of Cu2+salt containing 0.4gofCu2+is electrolysed until all the copper is deposited. The electrolysis is continued for seven more minutes with the volume of solution kept at 100 mL and the current at 1.2 amp. The volume of gases evolved at NTP during the entire electrolysis:

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A solution containing one mole per litre of each   Cu ( N O 3 ) 2 ;AgN O 3 ;H g 2 ( N O 3 ) 2 ;  is being electrolysed by using inert electrodes. The values of standard electrode potentials in volts are :

 Ag/Ag+=+0.80,  Hg2/Hg22+=+0.79Cu/Cu2+=+0.34,  Mg/Mg2+=2.37

With increasing voltage, the sequence of deposition of metals on the cathode will be :

MEDIUM
IMPORTANT

The equilibrium constant for the reaction,  2Fe3++3I2Fe2++I3 would be, if the standard reduction potentials in acidic conditions are 0.77 V and 0.54 V respectively for  Fe3+/Fe2+andI3/Icouple.

HARD
IMPORTANT

The standard potential of the following cell is 0.23 V at   15°C  and 0.21 V at   35°C .

 Pts|H2(g)|HCl(aq)|AgCl(s)|Ag(s)

 (ii) Calculate   ΔH°andΔS°  for the cell reaction by assuming that these quantities remain unchanged in the range 15°C to 35°C.

(iii) Calculate the solubility of AgCl in water at   25°C .

Given: The standard reduction potential of the  Ag+(aq)/Ag(s)  couple is 0.80 V at 25°C.

MEDIUM
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A standard hydrogen electrode has zero electrode potential because

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The emf of the cell:

Zn|Zn2+(0.01M)||Fe2+(0.001M)|Fe at 298 K is 0.2905 V. Then the value of equilibrium constant for the cell reaction is:

 

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Standard electrode potential data are useful for understanding the suitability of an oxidant in a redox titration. Some half cell reactions and their standard potentials are given below :

 MnO4(aq.)+8H+(aq,)+5eMn2+(aq.)+4H2O  (1)                                                                                                                                                          E°=1.51  VCr2O72(aq.)+14H+(aq.)+6e2Cr3+(aq.)+7H2O  (1)                                                                                                                                                           E°=1.38  VFe3+(aq.)+eFe2+(aq.)                                   E°=0.77  VCl2(g)+2e2Cl  (aq.)                                     E°1.40  V

Identify the only incorrect statement regarding the quantitative estimation of aqueous   Fe ( N O 3 ) 2

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When the samples of copper with zinc impurity is to be purified by electrolysis, the appropriate electrodes are –

MEDIUM
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The standard reduction potentials of some half cell reactions are given below :

PbO2+4H++2e-Pb2++2H2O  E0=1.455 V
MnO4-+8H++5e-Mn2++4H2O  E0=1.51 V
Ce4++e-Ce3+  E0=1.61 V
H2O2+2H++2e-2H2O  E0=1.71 V
Pick out the Incorrect statement :-

MEDIUM
IMPORTANT

For a galvanic cell Cr/Cr3+//cd2/Cd, calculated ΔG0 for its all reaction will be
ECr3+/Cr0=-0.74V,ECd2+/Cd0=-0.40 V

MEDIUM
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Given half-cell potentials ECr3+/Cr2+02+=-0.4 V and ECr2+/cr0=-0.91 V, find the standard reduction potential of Cr3+/Cr

EASY
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Standard hydrogen electrode (SHE) is a

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The standard reduction potential for Zn2+/ZnNi2+/Nand Fe2+/Fe are respectively -0.76, -0.23 and-0.44 V . The reaction X+Y2+X2++Y will have more negative ΔG value when X and Y are-

EASY
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EMF of a cell in terms of reduction pontential of its left and right electrodes is:

EASY
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The reaction is spontaneous if the cell potential is

MEDIUM
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E cell of the following electrochemical cell is: 

Als|Al+3aq. 1M||Zn2+aq. 1M|Zn s

(Given EAl=1.66 V, EZn= 0.76 V)

MEDIUM
IMPORTANT

The standard e.m.f. of the following cell is 0.463 V.

CusCu+ +1 MAg+1MAgs

If the standard potential of Ag electrode is 0.800 V, what is the standard potential of Cu electrode in volts?