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Electrochemistry

Question
CBSEENCH12006105

Calculate the standard free energy change for the reaction occuring in the cell:
Zn(s) | Zn2+ (1 M)|| Cu2+ (1M) | Cu(s)
[Given E°Zn2+/Zn = – 0.076 V, E°Cu2+/Cu = + 0.34 V, F = 96500 C mol–1]

Solution
Given:
EZn2+/Zn 0= – 0.076 V

ECu2+/Cu0 = + 0.34 V

F = 96500 C mol–1
from the reaction 
n=2

Ecell0 = ECu2+/Cu0 -  EZn2+/Zn 0


Ecell0 =0.34 -(-0.076)
        = 0.416

We know that
G = -nFEcell0

    =  -2 x 96500 x 0.416
     =–802.88 kJ mol
–1