Question

Depict the galvanic cell in which the reaction \[\ce{Zn_{(s)} + 2Ag+_{( aq)} -> Zn^{2+}_{( aq)} + 2Ag_{(s)}}\] takes place. Further show:

1. Which of the electrode is negatively charged?
2. The carriers of the current in the cell.
3. Individual reaction at each electrode.

Answer 1

The set-up will be similar to that shown below:

The cell will be represented as:

\[\ce{Zn_{(s)} | Zn^{2+}_{( aq)} || Ag^+_{( aq)} | Ag_{(s)}}\]

1. The zinc electrode (anode) is negatively charged because oxidation occurs at the anode.
2. 1. External circuit: Electrons flow from Zn to Ag, so the conventional current flows from Ag to Zn.
   2. Salt bridge: Ions carry the current.
3. At anode: \[\ce{Zn_{(s)} -> Zn^{2+}_{( aq)} + 2e–}\]
   At cathode: \[\ce{Ag+_{( aq)} + e- -> Ag_{(s)}}\]