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Me13 Electrolysis of salt water using the tin (Fe) of a Cola can as anode

 In the experiment for testing the electric conductivity of sea water chlorine was formed at a carbon anode.
In the following experiment you will replace carbon by a piece of cleaned Cola can tin (Fe). Universal indicator (UI) will be added to the water. A second experiment will be done without UI..Left: Use the closure of a Cola can (Al) as cathode, a cleaned piece of its tin (Fe) as anode.(The idea to the following experiments was published by El-Marsafy: chemarsafE35chemarsafE38) Observations Photo 2: Violet colour and gas bubbles at the cathode (Al),
* Anode (Fe): No change of indicator colour, no gas bubbles, no smell of chlorine.
Observations Photo 3 and right: During electrolysis without UI and stirring of the liquid a green solid is formed.
Explanations Reactions at the cathode:  2 H₂O + 2e^- -------red----> 2 OH^-(aq)  +  H₂ (g)
                       Reactions at the anode:                Fe (s) -----ox----> Fe²⁺(aq) + 2e^{-
                           Total reaction:}    2 H₂O + Fe (s) ---redox----> Fe(OH)₂(s)  + H₂ (g)
In this case the material of the anode was oxidized.