Identify the substance liberated at each electrode during the electrolysis of AgNO3 with inert electrodes.
I know that Ag is liberated at the cathode, but how about the anode?
Thanks in advance!
For aqueous electrolysis of AgNO₃, water would dominate at both electrodes. Generally, for an aqueous electrolytic process whose chemical reactions are driven by a battery …
The more negative Reduction Potential dominates at the cathode (site of reduction)
Ag⁺ + eˉ => Agᵒ ; Eᵒ = +0.80 volt
H₂O + 2eˉ => H₂ + 2OHˉ; Eᵒ = -0.83 volt => Dominate Rxn at Cathode
The more positive Reduction Potential dominates at the anode (site of oxidation)
NO₃ˉ + 4H⁺ + 3eˉ => NO + 2H₂O; Eᵒ = +0.96 volt
2H₂O => O₂ + 4H⁺ + 4eˉ ; Eᵒ = +1.23 volts => Dominate Rxn at the Anode
The net cell reaction would be 2H₂O => O₂ + 2H₂
Just an FYI, one should avoid considering melt electrolysis of nitrate systems => explosive! :-o
During the electrolysis of AgNO3 with inert electrodes, such as platinum or carbon electrodes, different substances are liberated at the cathode and the anode.
At the cathode (negative electrode), silver ions (Ag+) in the electrolyte will gain electrons and be reduced to form solid silver (Ag) atoms. This reduction reaction can be represented by the following equation:
Ag+ (aq) + e- → Ag (s)
So, silver metal is liberated at the cathode.
At the anode (positive electrode), nitrate ions (NO3-) in the electrolyte will lose electrons and undergo oxidation. However, since we have inert electrodes, they won't participate directly in the reaction. Instead, water molecules (H2O) in the electrolyte will undergo oxidation. The oxidation of water produces oxygen gas (O2) at the anode. The overall reaction can be represented by the following equation:
4OH- (aq) → 2H2O (l) + O2 (g) + 4e-
As a result, oxygen gas is liberated at the anode.
So, to summarize, during the electrolysis of AgNO3 with inert electrodes, silver metal (Ag) is liberated at the cathode, while oxygen gas (O2) is liberated at the anode.