EASY
Earn 100

Both E°cell and G° for the cell reaction are intensive properties.

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Important Questions on Electrochemistry

EASY
The standard emf of a galvanic cell involving 2 moles of electrons in its redox reaction is 0.59 V. The equilibrium constant for the redox reaction of the cell is:
MEDIUM

For the cell reaction

2Fe3+aq+2I-aq2Fe2+aq+I2aq

Ecell0=0.24V at 298 K. The standard Gibbs energy ΔrGo of the cell reaction is:

[Given that Faraday constant F=96500 Cmol-1 ]

MEDIUM
Given EMn+7|Mn+2=1.5 V and EMn+4|Mn+2=1.2 V, then EMn+7/Mn+4 is
MEDIUM
If the standard electrode potential for a cell is 2 V at 300 K, the equilibrium constant K for the reaction.

Zns+Cu2+aqZn2+aq+Cus 

at 300 K is approximately:

R=8 JK-1mol-1, F=96000 C mol-1
HARD

Relation between Gibb's Free Energy and EMF of a Cell Consider a 70% efficient hydrogen-oxygen fuel cell working under standard conditions at 1 bar and 298 K. Its cell reaction is

H2(g)+12O2(g)H2O(l)

The work derived from the cell on the consumption of 1.0×10-3 mol of H2(g) is used to compress 1.00 mol of a monoatomic ideal gas in a thermally insulated container. What is the change in the temperature (in K ) of the ideal gas?

The standard reduction potentials for the two half-cells are given below.

O2(g)+4H+(aq)+4e-2H2O(l),  E0=1.23 V,

2H+(aq)+2e-H2(g),  E0=0.00 V

Use F=96500 C mol-1,R=8.314 J mol-1K-1.

 

MEDIUM
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

The standard e.m.f. of the cell, CdsCdCl2aq0.1M|AgCls|Ags in which the cell reaction is Cds+2AgCls2Ags+Cd2+aq+2Cl-aq is 0.6915 V at 0°C and 0.6753 V at 25°C. The enthalpy change of the reaction at 25°C is

HARD

The standard electrode potential Eo and its temperature coefficient dEdT for a cell are 2V and -5×10-4 V K-1 at 300 K, respectively. The reaction is Zn s+Cu2+ aqZn2+ aq+Cu s. The standard reaction enthalpy ΔrH- at 300K in mol-1 is 

[Use R=8 J K-1 mol-1 and F=96,500 Cmol-1]

HARD
At 298 K, the standard reduction potentials are 1.51 V for MnO4- | Mn2+, 1.36 V for Cl2|Cl-, 1.07 V for Br2|Br-, 0.54 V for I2|I-. At pH=3, permanganate is expected to oxidize: RTF=0.059
HARD
The cell in which the following reaction occurs: 
2Fe3+aq+2I-aq2Fe2+aq+I2(s) has Ecell0=0.236 V at 298 K. Calculate the standard Gibbs energy and the equilibrium constant of the cell reaction. 
MEDIUM

The emf of the following cell is 1.229 V at 298 K.

Pt,H21atmH+1MO21atm,Pt 

H2+12O2H2O

The standard free energy change for the cell reaction is________ F=9.649×104 C mol-1

HARD

For the disproportionation reaction 2Cu+aqCus+Cu2+aq at 298K, lnK  (where K is the equilibrium constant) is _______×10-1

Given :E°Cu2+/Cu+=0.16V E°Cu+/Cu=0.52VRTF=0.025

MEDIUM
The standard free energy change for the cell reaction
Zn(s)+Cu(aq)2+Zn(aq)2++Cu(s) is EZn2+/Zn°=-0.76V,ECu2+/Cu°=+0.34V,1 F=96500Cmol-1
MEDIUM

The standard emf of the cell Ecell ° and equilibrium constant Keq of the following reaction of 298 K

Cd2++4NH3CdNH342+

MEDIUM
The emf of the cell Cd CdCl2 (solution) ( 1 atm) |AgCl(s)|Ag is 0.675 at 25°C. The temperature coefficient of the cell is -65×10-4 V degree-1 . Find the change in heat content (kJ mol-1 ) and entropy Vdeg-1 for the electrochemical reaction that occurs when 1 F of electricity is drawn for it
EASY
If the Ecello for a given reaction has a negative value, which of the following gives the correct relationship for the values of Go and Keq?
HARD

Calculate G° for the reaction Zn s + Cu2+ aq Zn2+ aq + Cu s

Given:

E° for Zn2+/Zn = -0.76VE° for Cu2+/Cu = +0.34VR = 8.314 JK-1 mol-1F = 96500 C mol-1

MEDIUM
The emf of a particular voltaic cell with the cell reaction, Hg22++H22Hg+2H+, is 0.65 V. What is the maximum electrical work of this cell when 0.5 g of H2 is consumed?