Question

Where does the oxidation take place in the Daniell cell?

Answer 1

Daniell cell:

• "Daniell converts the chemical energy liberated during the redox reaction to electrical energy."
• Consider the Daniell cell having electrodes of zinc and copper dipping in the solutions of their respective salts.

• The redox reaction taking place can be depicted as:

$\mathrm{Zn}\left(\mathrm{s}\right)+{\mathrm{Cu}}^{2+}\left(\mathrm{aq}\right)\rightleftharpoons {\mathrm{Zn}}^{2+}\left(\mathrm{aq}\right)+\mathrm{Cu}\left(\mathrm{s}\right)$

• In this redox reaction, Zinc is oxidized from $0$ oxidation state to $2+$ oxidation state while Copper is reduced from $2+$ oxidation state to $0$ oxidation state.
• In the Daniell cell, oxidation takes place at the anode while reduction takes place at the cathode.
• The reaction that takes place at the anode can be depicted as:

$\mathrm{Zn}\left(\mathrm{s}\right)\to {\mathrm{Zn}}^{2+}\left(\mathrm{aq}\right)+2{\mathrm{e}}^{-}$

• The reaction that takes place at the cathode can be depicted as:

${\mathrm{Cu}}^{2+}\left(\mathrm{aq}\right)+2{\mathrm{e}}^{-}\to \mathrm{Cu}\left(\mathrm{s}\right)$