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Question

Predict the products of electrolysis in each of the following:
An aqueous solution of AgNO3 with silver electrodes

Predict the products of electrolysis in each of the following:
An aqueous solution AgNO3 with platinum electrodes

Predict the products of electrolysis in each of the following;
A dilute solution of H2SO4 with platinum electrodes.

Predict the products of electrolysis in each of the following:
An aqeuous solution of CuCl2 with platinum electrodes.

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Solution

AgNO3 ionizes solutions to form Ag+ and NO3
On electrolysis, either Ag+ ions or H2O molecules can be reduced at the cathode. But the reduction potential of Ag+ ions is higher than that of H2O.
Ag+(aq)+eAg(s);E=+0.80 V
2H2O(l)+2eH2(g)+2OH(aq);E=0.83 V
Hence, Ag+ ions are reduced at the Cathode. Similarly, Ag metal or H2O molecules can be oxidized at the anode. But the oxidation potential of A is higher thatn that of H2O molecules.
Ag(s)Ag+(aq)+e;E=0.80 V
2H2O(l)O2(g)+4H+(aq)+4e;E=1.23 V
Therefore, Ag metals gets oxidized at the anode.

Pt cannot be oxidized easily. Hence, at the anode, oxidation of water occurs to liberate O2. At the cathode, Ag+ ions are reduced and get deposited.

H2SO4 ionizes in aqueous solutions to give H+ and SO24 ions.
H2SO(aq)2H+(aq);E=0.0 V
On electrolysis, either of H+ ions or H2O molecules can get reduced at the Cathode. But the reduction potential of H+ ions is higher than that of H2O molecules.
2H+(aq)+2eH2(g);E=0.0 V
2H2O(aq)+2eH2(g)+2OH(aq);E=0.83 V
Hence, at the cathode, H+ ions are reduced to liberate H2 gas.
On the other hand, at the anode, either of SO24 ions or H2O molecules can get oxidized.
But the oxidation of SO24 ions have a lower oxidation potential than H2O molecules.
Hence, SO24 ions have a lower oxidation potential than H2O is oxidized at the anode to liberate O2 molecules.

In aqeuous solutions, CuCl2 ionizes to give Cu2+ and Cl ions as:
CuCl2(aq)Cu2+(aq)+2Cl(aq)
On electrolysis, either of Cu2+ ions or H2O molecules can get reduced at the Cathode. But the reduction potential of Cu2+ is more than that of H2O molecules.
Cu2+(aq)+2eCu(aq);E=+0.34 V
H2O(l)+2eH2(g)+2OH;E=0.083 V
Hence, Cu2+ ions are reduced at the cathode and get deposited.
Similarly, at the anode, wither of Cl or H2O is oxidized. The oxidation potential of H2O is higher than that of Cl.
2Cl(aq)Cl2(g)+2e;E=1.36V
2H2O(l)O2(g)+4H+(aq)+4e;E=1.23 V
But oxidation of H2O molecules occur at a lower electrode potential than that of Cl ions because of over-voltage (extra voltage required to liberate gas). As a result, Cl ions are oxidized at the anode to liberate Cl2 gas.


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