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Question:

EMF of Daniell cell was found using different concentrations of Zn2+ ion and Cu2+ ion. A graph was then plotted between Ecell and log[Zn2+][Cu2+]. The plot was found to be linear with intercept in Ecell axis equal to 1.10V. Ecell for Zn/Zn2+(0.1M) || Cu2+(0.01M) will be:

1.10V

1.0705V

0.93V

0.078V

Solution:

For Daniell cell
Zn + Cu2+ → Zn2+ + Cu
Ecell = Eocell − 0.05912log[Zn2+][Cu2+]
Intercept, Eocell = 1.10V
∴Ecell = 1.10 − 0.05912log(0.1/0.01)
Ecell = 1.10 − 0.0295 = 1.0705V