Question

. Define oxidation and reduction.  Provide an example half reaction that is geochemically relevant for each type of reaction and identify the species being oxidized and the species being reduced

Answer 1

Oxidation : Oxidation is a loss of electrons or increse of oxidation number

Reduction : Reduction is a gain of electrons or decrease in oxidation number.

Example: Biodegradable of benzene by microorganism under oxidising geochemical conditions. In which benzene is oxidised by release of electrones and oxygen is reduced by gain of electrones. The half reaction canbe written as ;

                             C₆H₆   +    12 H₂O ​ CO₂ + 30 H⁺ + 30 e^-

                                 O₂   +   4H⁺    +   4e^-​ 2H₂O