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Question
Consult the table of standard electrode potentials and suggest three substances that can oxidise ferrous ions under suitable conditions.
Solution
Oxidation of ferrous ions means:
\[\ce{Fe^{2+} -> Fe^{3+} + e^-}\]; \[\ce{E^Θ_{{Fe^{3+}/Fe^{2+}}}}\] = 0.77 V
If the things that can change \[\ce{Fe^{2+}}\] to \[\ce{Fe^{3+}}\] are stronger oxidising agents and have positive reduction potentials higher than 0.77 V, then the cell reaction's EMF is positive. This applies to elements in the electrochemical series that are below \[\ce{Fe^{3+}/Fe^{2+}}\], such as \[\ce{Br2}\], \[\ce{Cl2}\] and \[\ce{F2}\].
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