redox reactions

Redox reactions

Chemical reactions involving the transfer of electrons between species, leading to changes in oxidation states.

Oxidation

An increase in the oxidation state of an element, typically involving the loss of electrons. Also defined as the loss of hydrogen or the gain of oxygen.

Reduction

A decrease in the oxidation state of an element, typically involving the gain of electrons. Also defined as the gain of hydrogen or the loss of oxygen.

Oxidising agent

The substance that is itself reduced in a redox reaction and causes the oxidation of another substance by accepting electrons.

Reducing agent

The substance that is itself oxidised in a redox reaction and causes the reduction of another substance by donating electrons.

Permanganate ion ( ext{MnO}\_4^-)

A strong oxidising agent, typically reduced from purple ext{MnO}\_4^- to colorless ext{Mn}^{2+} in acidic solution: ext{MnO}\_4^- + 8 ext{H}^+ + 5 e^- ightarrow ext{Mn}^{2+} + 4 ext{H}\_2 ext{O}

Dichromate ion ( ext{Cr}\_2 ext{O}\_7^{2-})

A common oxidising agent, typically reduced from orange ext{Cr}\_2 ext{O}\_7^{2-} to green ext{Cr}^{3+} in acidic solution: ext{Cr}\_2 ext{O}\_7^{2-} + 14 ext{H}^+ + 6 e^- ightarrow 2 ext{Cr}^{3+} + 7 ext{H}\_2 ext{O}

Iodide ion ( ext{I}^-)

A common reducing agent, oxidised to iodine ( ext{I}\_2): 2 I^- ightarrow I\_2 + 2 e^-