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# Redox Reaction Examples

Almost all the elements around us combine with molecular oxygen to form oxides and since the loss of electrons is now better known as oxidation due to loss after combining with oxygen. The metals of group I and group II form oxides that are best considered as ionic solids composed of metal cations and oxide anions. For every O2- anion a counter balancing cationic charge of +2 is also necessary. Like all transition metals, the non-metals form binary oxides of varying stoichiometry.

The stoichiometry of transition metal oxides is more variable, like iron (Fe) forms three binary oxides in which iron loses two and three electrons subsequently to either form Fe2O3 or Fe3O4, where one third of iron atoms have lost two electrons and two thirds have lost three. We can also understand that the more easily a metal is oxidised, the more quickly it reacts with molecular oxygen. Metals in every activity series at the bottom are always found in their elemental form in Earth’s crust. Almost all the metals react relatively quickly with oxygen to form insoluble oxides and these metals are found as minerals in nature. They can either have compounds with oxygen, sulfur, or polyatomic anions like carbonates or bicarbonates. Metallurgical processess combine chemistry and engineering to reduce metals in minerals to their specific elemental forms. We will be checking out on more such metals and their oxidised forms further in this article. These will help us get a better idea on how these forms of oxidised metals are involved with our daily life in their native and compound forms.

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## Redox Reaction Examples in Everyday Life

Almost one third of the chemical reactions that occurs around us involve oxidation and reduction reactions involving some common metals and these are seen when one chemical substance are transferred to another. The oxidation and reduction reactions include various forms of chemical changes that occur either abruptly or slowly. The rusting is a slow process while a cleaning of toilet is fast change or even the cooking of food from raw to edible is a quick process. But changes are inevitable and for every change there is either a gain or loss of electrons which makes a substance with form a compound or retain back their elemental form.
• Raw materials used in cooking getting converted into edible forms
• Rancidity of edible oil due to slow oxidation
• Rusting of metals, especially iron which is considered a slow process
• Cleaning of toilets using either mild acid or strong base combinations
• Change in food taste due to quick oxidation process or food getting waste due to rapid oxidation
• Experiments shown in labs to highlight the importance of group I and II metals
• Formation of various salts due to the reaction between base and acids
• Changing of mosquitoes coil into ash is also a type of oxidation reduction reaction as the ingredients used in coil go through rapid oxidation process to change their physical form
• Using of washing powder to pull out the dirt from clothes is again considered as oxidation reduction pattern where the detergent ingredients help in binding to dirt and make use of its hydrophilic end to pull it away from the fabric.

## Applications of Redox Reactions in Industry

The necessary connection of reduction with oxidation where one entity gains electrons while the other loses refers these as redox reaction or simply put reduction-oxidation reactions. For every final compound that is formed a definite change is observed and a reduction along with oxidation process has taken place.

The redox reaction are complicated than simple proton transfer reaction or any specific precipitation reaction because electrons transferred in redox chemistry do not seem to appear in balanced chemical equation. In order to showcase these reactions the use of half reaction is carried out to make use of the oxidation and reduction processes. A half reaction is a balanced chemical change equation that helps in understanding either the oxidation or reduction and not both at the same time. For any industrial process the knowledge of half reaction is very essential and can help assess the electrochemical requirements for the industrial applications.

The loss of electrons from one entity is used for bringing about the necessary changes in the next one or help gain electrons to bring about the changes and finally form the compound.

The application in industry are directed to extract the most possible benefit out of the entire process and hence the metal ions in solution are reduced to metals, or even displace one metal with another.

Oxidation:

$Zn (s) \rightarrow Zn^{2+} (aq) + 2e^-$

Reduction:

$Cu^{2+} (aq) + 2e- \rightarrow Cu (s)$

Redox process:

$Zn (s) + Cu^{2+} (aq) \rightarrow Zn^{2+} (aq) + Cu (s)$

These types of changes are made use in industry to either get a purified form of metal or to produce colourful artefacts with anoidic process.
• Purification of specific metals is carried out by using electrolysis method which is purely a redox process
• Displacing existing metals with a specific metal layer to give more strength and durability by redox process of electrolysis.
• Bringing out beautiful artefacts with anionised colour layering of metal over clay or other materials to give a metallic hue.
• The zinc layering is also carried out by using the redox electrolysis method to deposit specific amount of metal or layer of zinc
• The layering thickness is carried out by redox half reaction where the time and rate of deposition is controlled and monitored with the help of redox reaction.
• Electroplating of metals necessary for prevent rusting is carried out by redox reaction
• Anodising of artificial jewellery items

## Importance of Redox Reaction in Daily Life

The whole idea of redox lies in the fact that a metal transfers electrons to any cation which is lower in the electro positivity list.  This list is of the list of order of reactivity. In case the difference between these reactive metals is far and wide the reaction becomes very vigorous. The reaction begins only when a metal higher in reactivity series is added to a solution containing a cation lower in the list.

For example, $Ca (s) \rightarrow Ca^{2+} (aq) + 2e^{-} (oxidation)$

And reduction will take place when $Ni (s) + 2e^{-} \rightarrow Ni (s)$ but, redox as a whole will now show:

$Ca (s) + Ni^{2+} (aq) \rightarrow Ca^{2+} + Ni (s)$

The loss of electrons by active metals and help reduce the lesser metals in the series is something that occurs every day around us even when we are not actively participating or aware of these.

Chemical oxidation is a process in which the oxidation state of an atom is increased while the atom being oxidised can be in the elemental form or in a material in the form of molecule or ions.
• Use of antacid against acidic problem in stomach uses the same method of replacing active lower series metals with more active metals in electropositive series which helps in lowering the acidic environment within the stomach
• Using of bathroom cleaner where the more active ingredients help remove the lesser active materials in form of stain by redox exchanges
• Using toothpaste in the morning helps in removing plaque from teeth by using a more active ingredient in paste (calcium) and neutralising the effect on teeth.
• The use of various medicines to help cure disease uses the same redox patterns in removing toxic but lesser metal compounds with higher active metallic compounds
• The coupled reaction involving half reactions help get the right combination in food preparation as well. The more active ingredients help lose moisture from raw materials making them subtle and edible
• In any half reaction, the reactant which accepts electrons is termed as oxidant and hence, the active sodium potassium pump is considered as reductant series which helps in the continuation of the pump action for better heart working
• Metal polishing ingredients remove the lesser active oxidised layers from metal surface and help in bringing back the shine
• The battery cell we use in watches, remote controls, and various other household gizmos where redox reaction application works out within the electrochemical cells.
• The process of photosynthesis which is carried out day in and day out by trees around us follows the same redox reaction exchange
• The changes that we get to see in butter and other types of vegetable oil products turning rancid due to oxidation reduction exchanges
• Metals which get extracted from blast furnace by either oxidising the more active ingredients while reducing the intended metal for use in daily life
• Removing rust from metals by using more active ingredient solution
• The daily use of firewood that we get to use for either cooking or various other activities involves the same redox changes
• Drying of clothes in Sun involves the same redox exchanges that we see around us
• During festivals we burn crackers to celebrate uses the redox exchanges
• The quantitative analysis we make use of to explain chemical processes in school to students involve the same redox chemical exchanges

## Redox Reaction Examples Basic Solution

The redox reactions which involves the ions in solution include a varied selection of redox reactions involving pairs of ions and arranged as per the reagent and then within each of these ionic pair the ordering is carried out according to the rate constant.

Reactions in aqua metal ionic solution which are basic in nature gets hydrated with free electrons very fast and with the rate constant approaching diffusion controlled limit. Reactions carried out in perchlorate or cobalt solutions and even peroxo disulphate solution complexes.

The redox changes which are carried out in basic solutions differ from other forms of redox exchanges as these are carried out to maintain the hydroxide ions instead of the hydrogen ions. The hydroxide ions combine with hydronium ions to form water molecules. In order to balance the redox reaction under basic conditions involve two half reactions of both oxidation and reduction.

The reaction of ferrous ions in basic conditions.

$Fe^{2+} (aq) + MnO_{4} ^{-} (aq) \rightarrow Fe^{3+} (aq) + Mn^{2+} (aq)$

The reaction under basic conditions is as follows:

$MnO_{4} ^{-} (aq) + 5 Fe^{2+} (aq) + 4 H_{2}O (l) \rightarrow Mn^{2+} (aq) + 5 Fe^{3+} (aq) + 8 OH^{-} (aq)$

## Disproportionation Redox Reaction Examples

These disproportionation reactions occur when a single species is oxidised and reduced at the same time. These occurs when an element is present in a form which can be both oxidised as well as reduced. It is common for any element that has several oxidation states like sulphur and carbon etc. which makes it possible for finding a middle of these ranges.

$H_{2}O_{2} (aq) \rightarrow H_{2}O (l) + ½ O_{2}(g)$

$3 Br_{2} (aq) + 6 NaOH (aq) \rightarrow 5 NaBr (aq) + NaBrO_{3] (aq) + 3 H_{2]O (l)$

Here, the bromine starts at oxidation number zero and is then reduced to bromide ion, with a oxidation number -1, and then finally is oxidised to bromate ion $(BrO_{3} ^{-})$ with a oxidation number of + 5.

$Cl_{2] (g) + H_{2}O (l) \rightarrow HOCl (aq) + HCl (aq)$

In the above mentioned reaction, the chlorine atoms of chlorine molecule turns into chloride ion and the oxidation number changes from zero to -1. The other chlorine atom in the chlorine molecule becomes a part of chlorate ion. The oxidation number changes from zero to +1.

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