Question

Write the cell notation for an electrochemical cell consisting of an anode where Co (s) is oxidized to Co2+ (aq) and a cathode where Fe3+ (aq) is reduced to Fe2+ (aq) at a platinum electrode . Assume all aqueous solutions have a concentration of 1 mol/L and gases have a pressure of 1 bar.

Answer 1

Answer: The cell notation for the given cell will be:  $Co/Co^{2+}(1M,aq.)||Fe^{3+}(1M,aq.)/Fe^{2+}(1M,aq.)|Pt(s)$

Explanation:

The half cell reaction follows:

Oxidation half reaction:  $Co(s)\rightarrow Co^{2+}(1M,aq.)+2e^-$

Reduction half reaction:  $Fe^{3+}(1M,aq.)+1e^-\rightarrow Fe^{2+}(1M,aq.)$    ( × 2)

Net reaction:  $Co(s)+2Fe^{3+}(1M,aq.)\rightarrow Co^{2+}(1M,aq.)+2Fe^{2+}(1M,aq.)$

Oxidation reaction always occurs at anode.

Cell notation is the representation in which, the anode is written on left hand side followed by its ion with its molar concentration. It is then followed by a salt bridge, which is represented by the symbol "||" . Then the cathodic ion with its molar concentration is written and then the cathode.

Hence, the cell notation for the given cell will be:  $Co/Co^{2+}(1M,aq.)||Fe^{3+}(1M,aq.)/Fe^{2+}(1M,aq.)|Pt(s)$