Thermodynamics of Cell

IMPORTANT

Thermodynamics of Cell: Overview

This Topic covers sub-topics such as Relation between Gibbs Free Energy and EMF of a Cell, Relation between Equilibrium Constant and EMF of a Cell and, Work Done by a Cell

Important Questions on Thermodynamics of Cell

MEDIUM
IMPORTANT

Zinc granules are added in excess to a 500 mL of 1.0 M nickel nitrate solution at   25°C  until the equilibrium is reached. If the standard reduction potential of  Zn2+/Zn  and  Ni2+/Ni  are  0.75  V  and  0.24  V  respectively, the concentration of  Ni2+  in solution at equilibrium.

HARD
IMPORTANT

The standard reduction potential at   25°C of the reaction,   2 H 2 O+2 e H 2 +2O H is0.8277V.  The equilibrium constant for the reaction   2 H 2 O H 3 O + +O H  at   25°C.

HARD
IMPORTANT

An excess of liquid mercury is added to an acidified solution of 1.0× 10 3 MF e 3+ .  It is found that 5% of   F e 3+ remains at equilibrium at  25°C.  Calculate   E ( H g 2 2+ /Hg ) 0 ,  assuming that the only reaction that occurs is   2Hg+2F e 3+ H g 2 2+ +2F e 2+ . (Given   E ( F e 3+ /F e 2+ ) 0 =0.77V) :

EASY
IMPORTANT

What is the equilibrium constant for the reaction,  2Fe3++3I2Fe2++I3, if the standard reduction potentials in acidic conditions are 0.77 V and 0.54 V for  Fe3+Fe2+ and I3I couples, respectively?

HARD
IMPORTANT

The equilibrium constant for the reaction would be:

Feaq2++Ceaq3+Ceaq2++Feaq3+ Given that ECe3+/Ce2+o=1.44V, EFe3+/Fe2+o=0.68V

HARD
IMPORTANT

Find the equilibrium constant for the reaction,

  Cu 2 + + In 2 + Cu + + In 3 +

Given  ECu2+/Cu+o=0.15V, EIn2+/In+o=-0.40V, EIn3+/In+o=-0.42V

HARD
IMPORTANT

For the reaction

Agaq++Claq-AgCls

Given:

Species Gf(kJ mol-1)
Ag+aq +77
Cl-aq -129
AgCls -109

Calculate   at298K.

ΔGreaco  represent the reaction as cell calculate Ecello & find  log10 Ksp for  AgCl.

HARD
IMPORTANT

The Edison storage cell is represented as:

 Fe(s)|FeO(s)|KOH(aq)|Ni2O3(s)|Ni(s)

The half-cell reactions are:

 Ni2O3(s)+H2O(l)+2e2NiO(s)+2OHaq-;                                                                                                  E°=+0.40 VFeO(s)+H2O(l)+2eFe(s)+2OHaq-;                                                                                                   E°=0.87 V

The cell e.m.f. and the maximum amount of electrical energy that can be obtained from one mole of Ni2O3?

HARD
IMPORTANT

The rusting of iron takes place as follows
2Haq++2e+12O2gH2Ol;E°=+1.23V
Feaq2++2e Fe(s) ;E°=0.44 V

Calculate  ΔG°for the net process:

HARD
IMPORTANT

The emf of the cell

Zn/Z n 2+ ( 0.01 )||F e 2+ ( 0.001M )/Fe at 298 K is 0.2905 then the value of equilibrium  constant for the cell reaction is

 

HARD
IMPORTANT

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:

 

HARD
IMPORTANT

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+5e-Mn2+aq+4H2Ol ; Eo=1.51V

Cr2O72-aq+14H+aq+6e-2Cr3+ aq+7H2Ol ; Eo=1.38V

Fe3+aq+e-Fe2+aq ; Eo=0.77V

Cl2g+2e-2Cl-aq ; Eo=1.41V

Identify the only incorrect statement regarding the quantitative estimation of aqueous FeNO32.

MEDIUM
IMPORTANT

The standard e.m.f. of a galvanic cell involving cell reaction with n = 2 is found to be 0.295 V at   25°C.  The equilibrium constant of reaction would be –

EASY
IMPORTANT

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R:

Assertion A: In equation rG=-nFEcell value of rG depends on n.
Reason R: Ecell is an intensive property and rG is an extensive property.

In the light of the above statements, choose the correct answer from the options given below:

MEDIUM
IMPORTANT

H2(g)+2AgCl(s)2Ag(s)+2HCl(aq)

Ecell° at 25°C for the cell is 0.22 V. The equilibrium constant at 25°C is

MEDIUM
IMPORTANT

For a cell involving one electron Ecell=0.59 V at 298 K, the equilibrium constant for the cell reaction is:
Given that 2.303 RTF=0.059 V at T=298 K 

MEDIUM
IMPORTANT

For a cell reaction involving two-electron changes, Ecell=0.3 V at 25°C. The equilibrium constant of the reaction is

EASY
IMPORTANT

What is the approximate standard free energy change per mole of Zn (in kJ mol-1) for a Daniel cell at 298 K?

EASY
IMPORTANT

For the cell reaction 3Sn4++2Cr3Sn2++2Cr3+,E°cell is 0.89 V. Then ΔG° for the reaction is

HARD
IMPORTANT

ΔG° for the reaction Ag+(aq)+12H2(g)H+(aq)+Ag(s), where standard potential for silver half cell reaction is 0.8 V, will be