Question

Consider the following half-reactions and their standard reduction potentials then give the standard line (cell) notation for a voltaic cell built on these half reactions. Mn2+(aq) + 2 e- <=> Mn(s) E° = -1.18 V Fe3+(aq) + 3 e- <=> Fe(s) E° = -0.036 V

Answer 1

Answer:

$Mn(s)|Mn^{2+}(aq)||Fe^{3+}(aq)|Fe(s)$

Explanation:

The given half reactions are:

$Mn^{2+}(aq)+2e^{-}\rightarrow Mn(s).....E^{0}=-1.18V$

$Fe^{3+}(aq)+3e^{-}\rightarrow Fe(s).....E^{0}=-0.036V$

where E° is the standard reduction potential.

The electrode with a higher (more positive) reduction potential serves as the cathode.

Here, E°(Fe3+/Fe) > E°(Mn2+/Mn)

Hence Fe3+/Fe = cathode

Mn2+/Mn = anode

As per convention, the cell notation is represented such that the anode half cell is on the left and cathode on the right. Both a separated by a salt bridge represented by the symbol ('||')

Cell notation:

$Mn(s)|Mn^{2+}(aq)||Fe^{3+}(aq)|Fe(s)$