17.4 Exercise 3

Determine the standard cell potential and the cell potential under the stated conditions for the electrochemical reactions described here. State whether each is spontaneous or nonspontaneous under each set of conditions at 298.15 K.

(a) $\text{Hg} \left(l\right) + \text{S}^{2−} \left(a q ,\text{ 0}.\text{10} M\right) + 2 \text{Ag}^{+} \left(a q ,\text{ 0}.\text{25} M\right) \rightarrow 2 \text{Ag} \left(s\right) + \text{HgS} \left(s\right)$

(b) The cell made from an anode half-cell consisting of an aluminum electrode in 0.015 M aluminum nitrate solution and a cathode half-cell consisting of a nickel electrode in 0.25 M nickel(II) nitrate solution.

(c) The cell comprised of a half-cell in which aqueous bromide ion (1.0 M) is being oxidized to aqueous bromine (0.11 M) and a half-cell in which Al³⁺ (0.023 M) is being reduced to aluminum metal.