Two redox reactions at 298 K have the following standard cell potentials and numbers…

CHEMISTRY · Single correct · A Level · Chemistry · Electrode potentials · Electrode potentials

Problem

Two redox reactions at 298 K have the following standard cell potentials and numbers of electrons transferred. Reaction X:

n=2

E^{\circ}=+0.30\,\text{V}

Reaction Y:

n=3

E^{\circ}=+0.20\,\text{V}

Let

K_X

and

K_Y

be the corresponding equilibrium constants. Which statement correctly compares their magnitudes? (a)

K_X>K_Y

because the equilibrium constant depends only on the standard cell potential, which is larger for Reaction X. (b)

K_X<K_Y

because the larger number of electrons transferred in Reaction Y makes

\log K

larger. (c)

K_X=K_Y

because the product

nE^{\circ}

is identical for both reactions. (d) The relationship between

K_X

and

K_Y

cannot be determined without knowing the absolute temperature.