27. THEORY OF OXIDATION REDUCTION REACTIONS.

After discovery of oxygen, the French chemist Lavoisier managed to find out that burning is reaction of connection with oxygen. In compliance the Latin name of oxigenium oxygen of reaction of connection with oxygen have been called oxidation.

^2Mg0 _{+O20=2Mg+2O-2}

Reverse full or partial oxygen otnyatiya from substances is called recovery. At oxide recovery the element connected to oxygen changes the state - forms simple substance, i.e. is recovered.

_{Fe2+3O3-2+2Al0=Al2+3O3-2+2Fe0}

You have noticed that in these reactions oxidation levels of chemical elements have changed. Chemical reactions from which change of oxidation levels of atoms of the chemical elements or ions forming the reacting substances results are called oxidation reduction reactions.
In compliance oxidation and recovery easily has a talk with the theory of electronic atomic structure as process of return or accession of electrons. In oxidation reduction reactions electrons do not leave the sphere of reaction, and are transferred from one element to another.
Let's consider reaction of interaction of magnesium with oxygen.

From the scheme it is visible that atom of magnesium has given 2 electrons to oxygen atom, due to such transition chemical elements have changed oxidation levels. Two processes proceed. Process of return of electrons and process of their accession which are called respectively oxidation and recovery.
The substances participating in oxidation reduction reactions and at which oxidation levels have changed are either okislitelyamiya, or reducers.
The oxidizer is atoms, ions or molecules which accept electrons.
The reducer is atoms, ions or molecules which give electrons.
From the equation of reaction it is visible that magnesium is reducer, and oxygen - oxidizer.

Remember! The reducer in chemical reaction is always oxidized, the oxidizer - is recovered.

The major reducers and oxidizers.

  

 

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