Daniell Cell in Electrolytic Mode

If we want to rnn the Daniell cell as an EC, in a way opposite to the galvanic mode, and carry ont electrolysis, we should apply a potential using a battery or any other direct cnrrent (dc) power supply. The magnitude of E c should be larger than that of the eqnilibrinm potential of the EC, that is, lEgc I I E qI and this causes the current to flow in the opposite direction of the current in a GC, as shown in Eigure 2.11. 

we shonld nse the decomposition potential (Ejy) rather than equilibrium potential (Eeq)- The decomposition potential is the minimum theoretical potential at which electrolysis takes place. is directly related to the equilibrium potential of the GC as follows  

Because the Gibbs energy of any electrolytic reaction is positive (electrolytic reaction is not spontaneous), the decomposition potential is always negative, while the equilibrium potential of the GC is always positive. The relationship between the potential difference of the EC or simply the applied potential ( ec) the decomposition potential (Ed), current in the EC (/gc). and the internal resistance (R,) is as follows  

FIGURE 2.11 The Daniell cell in electrolytic mode the cathode is negatively charged and the anode is positive with respect to the cathode. 

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