{"id":61,"date":"2016-08-23T15:56:47","date_gmt":"2016-08-23T15:56:47","guid":{"rendered":"http:\/\/www.experimentoscientificos.es\/?p=61"},"modified":"2022-03-19T14:27:36","modified_gmt":"2022-03-19T14:27:36","slug":"reacciones-redox","status":"publish","type":"page","link":"https:\/\/www.experimentoscientificos.es\/en\/reacciones-redox\/","title":{"rendered":"Redox reactions"},"content":{"rendered":"

One of the chemical reactions<\/a> most important, together with the acid-base reactions<\/a>are the redox reactions<\/strong>. In redox reactions, or oxidation-reduction reactions,\u00a0<\/strong>\u00a0an exchange of electrons takes place between the components of the reaction. In order to be able to see their importance, before analysing what these reactions consist of, we are going to see in which situations in our day-to-day life these reactions are taking place as well as other applications.<\/p>\n

OXIDANT AND REDUCTANT IN REDOX REACTIONS<\/h2>\n

Whenever we have an oxidation-reduction reaction we are always going to have an oxidation-reduction reaction. oxidant<\/strong> and a reducer<\/strong>.<\/p>\n

OXIDANT:<\/strong> The oxidant gains electrons<\/strong>and is therefore reduced. One of the main oxidants is oxygen, it tends to gain electrons, oxidising for example metals as we know them.
\nREDUCER:<\/strong> The reductant loses electrons, and is therefore oxidised.<\/p>\n

EXAMPLES OF REDOX REACTIONS<\/h2>\n

Redox reactions are permanently present in our daily lives and understanding the process can help you understand how many natural processes work. From obtaining heat from coal, the oxidation of iron that we all know as rusty iron, the ageing of the skin, the reason why food degrades...<\/p>\n

EXAMPLE OF HEAT PRODUCTION FROM COAL<\/h3>\n

(Although it is a redox reaction, reactions involving carbon and hydrogen to give heat are called combustion reactions<\/a>but the process followed by these reactions is an oxidation-reduction process).<\/p>\n

C+O2<\/sub> -> CO2\u00a0<\/sub><\/strong><\/p>\n

This would be the reaction that occurs when burning coal. Carbon (0) is oxidised to carbon ion C4+ and oxygen is reduced from the molecule O2, with oxidation state to oxygen ion 2-. This molecule is known as carbon dioxide. This reaction needs an activation energy but once started the oxidation of carbon continues to release CO2 and heat.<\/p>\n

EXAMPLE IRON OXIDATION<\/h3>\n

Let's take a look at an example of the reactions that occur with the oxidation of iron, a fact that we have all experienced at one time or another.<\/p>\n

4Fe + 3O2 \u2192 2Fe2O3<\/strong><\/p>\n

As soon as the iron comes into contact with air, an oxidation process begins, where the oxygen, O2, will gain 2 electrons (it will be reduced, acting as an iron oxidant) and the iron will lose them (it oxidises), going from oxidation state 0 to Fe3+, forming the new iron oxide compound. This process is accelerated if the iron is introduced into an aqueous medium, and the more salt the medium contains, the more it favours the circulation of electrons (hence there is no piece of iron in seawater that can resist).<\/p>\n

ELECTRONEGATIVITY<\/h2>\n

In a redox reaction, to know who is oxidised and who is reduced, it is necessary to know which is the most electronegative element. The electronegativity is calculated using tables, with hydrogen as a reference. See electronegativity tables.<\/p>\n

EXPERIMENTS WITH REDOX CHEMICAL REACTIONS<\/h2>\n

Redox reactions often produce quite violent reactions, so when performing redox chemical reaction experiments, you need to know what you are doing.
\n

\n
\n\n\n
\n\t\"grabar<\/a>\n<\/div>\n
\n
\n\n

Etch Iron Plate (Redox between Copper Sulphate and Iron)<\/a><\/h3><\/div>\n\n<\/strong> In this experiment we are going to make a practical application of what would be an oxidation-reduction reaction by etching a sheet of iron.<\/div>\n\n<\/div>\n
<\/div>\n<\/div>\n
<\/div>\n\n\n\n
\n\n\n
\n<\/div>\n
\n
\n\n

Reaction between Glycerine and Potassium Permanganate<\/a><\/h3><\/div>\n\n<\/strong> Display reaction between vegetable glycerine and potassium permanganate. In this case the potassium permanganate causes the glycerol to combust instantaneously. <\/div>\n\n<\/div>\n
<\/div>\n<\/div>\n
<\/div>\n\n\n\n
\n\n\n
\n<\/div>\n
\n
\n\n

Sugar Carbonisation with Sulphuric Acid<\/a><\/h3><\/div>\n\n<\/strong> This experiment is a very striking experiment where you can see a sugar combustion reaction, produced by the dehydration of sugar through the action of sulphuric acid. <\/div>\n\n<\/div>\n
<\/div>\n<\/div>\n
<\/div>\n\n\n\n
\n\n\n
\n<\/div>\n
\n
\n\n

Sodium Metal Reaction in Water Experiment<\/a><\/h3><\/div>\n\n<\/strong> In this experiment you can see the instantaneous and violent reaction of sodium in water. <\/div>\n\n<\/div>\n
<\/div>\n<\/div>\n
<\/div>\n\n\n\n
\n\n\n
\n<\/div>\n
\n
\n\n

REDOX Reaction Copper Iron Sulphate<\/a><\/h3><\/div>\n\n<\/strong> Experiment on the oxidation of copper sulphate with iron. In this reaction, the iron would be oxidised and the copper would be reduced, depositing a layer of copper on the iron. <\/div>\n\n<\/div>\n
<\/div>\n<\/div>\n
<\/div>\n\n\n\n
\n\n\n
\n<\/div>\n
\n
\n\n

Producing Hydrogen, H2, with Aluminium and HCl<\/a><\/h3><\/div>\n\n<\/strong> An exhibition-only experiment where hydrogen gas can be produced by mixing an acid with metal. Be very careful with hydrogen.<\/div>\n\n<\/div>\n
<\/div>\n<\/div>\n
<\/div>\n\n\n\n
\n\n\n
\n<\/div>\n
\n
\n\n

Elephant Toothpaste<\/a><\/h3><\/div>\n\n<\/strong> In this experiment, hydrogen peroxide will be decomposed, releasing a large amount of oxygen, which, mixed with soap, will produce a large amount of foam. <\/div>\n\n<\/div>\n
<\/div>\n<\/div>\n
<\/div>\n\n\n\n
\n\n\n
\n<\/div>\n
\n
\n\n

Oxidation Hydrogen Peroxide with Potassium Permanganate (Genie Lamp)<\/a><\/h3><\/div>\n\n<\/strong> Spectacular experiment known as the genie of the lamp because of the large amount of smoke that is instantly released. With hydrogen peroxide and permanganate. <\/div>\n\n<\/div>\n
<\/div>\n<\/div>\n
<\/div>\n\n\n\n
\n\n\n
\n<\/div>\n
\n
\n\n

REDOX Reaction - Copper Aluminium Sulphate<\/a><\/h3><\/div>\n\n<\/strong> In this experiment we will look at the oxidation of copper sulphate on aluminium. It is a way of electroplating aluminium with copper. It is a simple experiment where you can see a redox reaction. <\/div>\n\n<\/div>\n
<\/div>\n<\/div>\n
<\/div>\n\n\n <\/div><\/p>\n

REDOX CHEMICAL REACTIONS IN NATURE<\/h2>\n