Effects of Oxidation in Everyday Life
To understand the effects of oxidation state and its effect on everyday life we need to understand oxidation and more so the related reaction reduction as well.
The reduction and oxidation reaction or redox reaction is a chemical reaction during which the oxidation state of two or more of the reactants change. Oxidation reaction is not only about just combining with oxygen.
Most redox reactions do not even involve oxygen at all.
The oxidation state of an atom or icon can be thought of as its electrical charge and in simple terms a neutral atom is in oxidation state zero. An ion with a positive charge has a positive oxidation state overall loses an electron and it has been oxidized to oxidation state 1+ and becomes a positive ion.
Oxidation in the context of a redox reaction refers to the oxidation state of an atom being increased.
Conversely reduction refers to oxidation state of an atom being reduced.
Many chemical reactions do not involve any change in oxidation state.
For example when we react aqueous solutions of copper (II) sulphate and sodium hydroxide to form copper (II) hydroxide which precipitates and a solution of sodium sulphate forms and there are no changes in oxidation state.
Oxidation is the process of addition of oxygen or any electronegative radical or removal of hydrogen or electropositive radical. It’s a process in which an atom or a group of atoms taking part in a chemical reaction loses one or more electrons.
The species which undergo the loss of electron during the reaction is called as reducing agent or reductant.
An oxidation reaction is always couple with reduction reaction which refers as addition of electron to the reaction species (Oxidant or oxidising agent).
These coupled reactions are known as redox reaction.
When a substance exposes to oxygen, it gets oxidised.
We can observe many oxidation reactions in our daily life like corrosion of metal, rancidity and combustion.
Let’s discuss some of the common examples of oxidation reaction;
Combustion: it is the most common example of oxidation reaction.
Combustion or burning of any material involves oxidation reaction coupled with reduction.
The complete combustion of substance generally released carbon dioxide and water.
For example the burning of wood released a large amount of energy with carbon dioxide and water vapour.
That energy uses for heating home, drive automobile, operate industrial processes and much other purpose.
Corrosion: You must have seen the rusting of your car and the burning of magnesium metal in oxygen to form magnesium oxide in your daily life are also an oxidation reaction.
Similarly rusted iron sheets or green surface of copper utensils and tableware or tarnish surface of aluminium surfaces are also due to oxidation of metal surface.
Most of metal surfaces oxidised due to atmospheric oxygen and forms metal oxides on the surface of metal.
For example; corrosion of iron forms iron oxide which is also called as rust.
4Fe +3O2 ==> 2Fe2O3
Similarly copper utensil gets a greenish glaze due to formation of copper oxide which grants it strength.
The oxidation of metal surfaces may be preventing by means of painting and or by galvanization with zinc.
Anodization, plating, painting of anti-corrosive substances or coating of corrosion inhibitors used to prevent corrosion on metal surface. Some time sacrificial corrosion also helps to prevent corrosion, in which more reactive metal coupled with corrode metal to stop the corrosion.
Like magnesium wire bonded on iron pipe decrease the corrosion on pipe as it starts with more reactive magnesium metal.
Battery: We are very much familiar a highly useful application of electrochemistry in our daily life in the form of batteries which use oxidation-reduction reactions to produce an electric current.
For example lead storage battery mainly use in automobile contains lead as reducing agent and lead (IV) oxide (PbO2) as oxidizing agent. Other examples are dry cell batteries, nickel-cadmium battery etc.
Coinage Metals: Copper and silver are termed as coinage metals due to their resistance to corrosion.
As both metals become tarnish due to formation of copper oxide and silver sulphide.
Rancidity: Oxidation reactions are also responsible for the spoiling of food.
To prevent spoilage, manufacturers of food items often add preservatives, which act as reducing agents or antioxidants like vitamin C and vitamin E.
Metabolisms of food, cellular respiration, regulation of enzyme in human body, photosynthesis are also examples of oxidation reaction.
We literally cannot live without the common or everyday life oxidation reactions and here are a few examples of those:
(a) Water purification uses redox reactions to oxidize coloured and bad tasting or otherwise not pure or very good in taste to forms that are safe and acceptable.
(b) Bleaches used in laundry, papermaking and other processes are all basically depend upon redox reactions to oxidize all colored stains and impurities to colorless compounds.
(c) Metals that are all mined are basically in form of oxides. The process that help these oxides of metals to reduce these in a positive oxidation into neutral metallic forms.
(d) The photographic film works by a redox reaction initiated by light reaction and when photons strike the tiny grains of silver bromide cause the silver ions to reduce to microscopic specks of metallic silver. The picture is visible after clearing away the un-reduced silver.
(e) Corresions and rusting are another set of examples which involve reduction and oxidation and anything made up of iron are prone to atmospheric oxygen in the presence of moisture and forms the rust or iron oxides.
(f) The aluminium items we use in kitchen also undergo oxidation in presence of atmospheric oxygen. The silvery color of aluminium when these are brand new turns darkish after few days due to the formation of the protective cover of aluminium oxide.
(g) The silver items form a protective cover over the metal and turn little dark by forming silver oxide by reacting with atmospheric oxygen.
Everything and almost anything undergoes oxidation and some of these show stark visible changes to make them noticeable.