Q. 20

# = 1.1 V for Daniel cell. Which of the following expressions are correct description of state of equilibrium in this cell?

A. 1.1 = K_{c}

B.

C.

D. log K_{c} = 1.1

Answer :

The electrode potential of any cell compared to standard hydrogen electrode is given by the Nernst equation, . Where E^{0} is the standard cell potential, R is the universal gas constant, T is the temperature in Kelvin, F is the Faraday constant, [M^{n+}] is the concentration of the electrolyte.

For a Daniell cell, the cell potential is given in the following equation after converting the natural logarithm to the base 10 and substituting the values of R, F and T = 298 K –

E_{cell} = - .

At equilibrium,

E_{cell} = 0. So, E^{Ө}_{cell} =

K_{c} = [Zn^{2+}]/[Cu^{2+}]

So the equation can also be written as

E^{Ө}_{cell} =

From these equations, it can be calculated that (ii) and (iii) are correct.

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