# What is the standard cell notation of a galvanic cell made with silver and nickel?

Jun 2, 2016

$N i \left(s\right) | N {i}^{2 +} \left(a q\right) \setminus | | \setminus A {g}^{+} \left(a q\right) | A g \left(s\right)$

#### Explanation:

Start by finding the standard reduction potential for the $A {g}^{+}$ and $N {i}^{2 +}$ ion. Normally, the values are listed at the back of most chemistry textbooks.

$A {g}^{+} \left(a q\right) + 1 {e}^{-} \to A g \left(s\right) \text{ } {E}^{o} = 0.80 \setminus V$
$N {i}^{2 +} \left(a q\right) + 2 {e}^{-} \to N i \left(s\right) \text{ } {E}^{o} = - 0.23 \setminus V$

In the galvanic cell, the reaction is spontaneous and for a spontaneous reaction ${E}_{c e l l}^{o}$ must be a positive quantity.

${E}_{c e l l}^{o} = {E}_{A n o \mathrm{de}}^{o} + {E}_{c a t h o \mathrm{de}}^{o}$

Manipulate the two equations so that ${E}_{c e l l}^{o}$ is positive. Note that the anode is the site of oxidation (where electrons are lost) and the cathode (where electron are gained) is the site for reduction.

$A {g}^{+} \left(a q\right) + \textcolor{red}{1 {e}^{-}} \to A g \left(s\right) \text{ } {E}^{o} = 0.80 \setminus V$
$N i \left(s\right) \to N {i}^{2 +} \left(a q\right) + \textcolor{red}{2 {e}^{-}} \text{ } {E}^{o} = 0.23 \setminus V$

$2 \times \left\{A {g}^{+} \left(a q\right) + 1 {e}^{-} \to A g \left(s\right)\right\} \text{ " E^o= 0.80 \ V " } \textcolor{red}{\left(C a t h o \mathrm{de}\right)}$
$N i \left(s\right) \to N {i}^{2 +} \left(a q\right) + 2 {e}^{-} \text{ " E^o= 0.23 \ V " " color(red)((Anode)}$
$\underline{\text{ }}$
$2 A {g}^{+} \left(a q\right) + N i \left(s\right) \to N {i}^{2 +} \left(a q\right) + 2 A g \left(s\right) \text{ } {E}_{c e l l}^{o} = 1.03 \setminus V$

Start with the anode components (site of oxidation) - the cathode components are listed to the right.

$N i \left(s\right) | N {i}^{2 +} \left(a q\right) \setminus | | \setminus A {g}^{+} \left(a q\right) | A g \left(s\right)$

The single vertical lines indicate the boundary (phase difference) between solid $N i$ and $N {i}^{2 +}$ ions in the aqueous solution of the first compartment and between solid $A g$ and $A {g}^{+}$ ions present in the aqueous solution of the second compartments.

The double vertical lines refer to the salt bridge - note that the salt bridge must be an inert salt to both ions present in both compartments of the galvanic cell ...