We can use aluminium in place of zinc for cathodic protection of rusting. Comment.

 In cathodic protection the metal (here iron) to be protected from corrosion is connected by a wire to a more anodic matal ( like Al, Zn etc), so that all the corrosion occurs at this more active metal. Thus the parent metal is protected while the more active metal gets corroded slowly.
As the standard electrode potential of aluminium is more than that of zinc so Al is more anodic than Zn.
Thus we can better use aluminium in place of zinc for cathodic protection of rusting of iron.
At anode : Al → Al3+ + 3e
At cathode : O2 + 2H2O + 4e --->4OH

1149 Views

Write the reactions taking place at the anode and cathode in the above cell.
When AgNO3 is electrolysis in aqueous solution?

AgNO3(aq)  Ag+(aq) + NO3-(aq)
At cathode:
Ag+(aq) + e-   Ag(s)
At anode:
        2H2O(I)   O2(g) + 4H+(aq) + e-

131 Views

How is cathodic protection of Iron different from its galvanisation?

In cathodic protection, the iron object is made cathode by connecting it with a more reactive metal like Mg, Zn etc. whereas in galvanisation, the iron object is protected from corrosion by coating it with zinc.
185 Views

Advertisement

Give reactions taking place at the two electrodes if these are made up of Ag.


Electrolysis of AgNO3 using Ag electrodes
        AgNO3(aq)   Ag+(aq) + NO3-
At cathode:
          Ag+(aq) + e-      Ag(s)
At anode:
                Ag(s)     Ag+(aq) + e-

130 Views

Advertisement
A current of 1.50 amp passed through an electrolytic cell containing AgNOsolution with inert electrodes. The weight of Ag deposited was 1.50 g. How long did the current flow?

Ag+ + e-    Ag1 mol                1 mol(or 108 g)
108 g of silver needs  = 1 Faraday
                       = 96500 coulombs
 1.50 g of silver needs  = 96500×1.50108
                             = 1340.3 coulomb
But               Q      = current x time
               1340.3   = 1.5A x time (in sec)
Time for which current is passed  = 1340.31.5
                                                     = 893.5 sec  = 14.9 min
1162 Views

Advertisement