In the dictionary of Digopaul, the concept of reducing agent is used in the field of chemistry, in the framework of reduction-oxidation reactions (also known as redox reactions). In these reactions, the reducing agent releases electrons that are accepted by the oxidizing agent. Said transfer implies a change in the oxidation state.
These reduction-oxidation reactions can be said to involve two half-reactions. On the one hand, the reducing agent loses electrons and rusts; on the other, the oxidizing agent adds electrons and is reduced.
Summarizing the development of redox reactions, we can say that the reducing agent gives up electrons and increases their oxidation number: that is, it oxidizes. The oxidizing agent, on the other hand, adds electrons and reduces their oxidation number (it is reduced).
Suppose there is a reaction between chlorine and calcium. In this case, calcium acts as a reducing agent since it releases electrons and its oxidation number increases from 0 to 2. Chlorine, on the other hand, acts as an oxidizing agent (sum of electrons).
It is important to note that reduction and oxidation always take place simultaneously. Every time a reducing agent acts in a reaction, there is also an oxidizing agent. The reducing agent is one that is oxidized in the reaction and that provides electrons.
The hydrogen, for example, is a reducing agent which is frequently used. It is possible to obtain copper metal in a reaction where hydrogen oxidizes and releases electrons.
Let’s see a list of other of the most used reducing agents, to appreciate more clearly the different applications that they can have:
* carbon monoxide: it is used in metallurgy to reduce metal oxides. The temperature used to reduce the ore in the blast furnace (the structure made to melt and reduce iron minerals for future smelting) is approximately 900 °C;
* Aluminum: since it is a chemical element (more precisely, a non-ferromagnetic metal) with a high chemical affinity for oxygen, metallurgy uses it as a reducing agent, and also to obtain those metals that are especially difficult to reduce, such as lithium and calcium, among others, through the procedure known as aluminothermic;
* coal: its hydrocarbon derivatives are also reducing agents, among which are propane, butane, methane and gasoline, in addition to organic compounds such as carbohydrates and fats. In the combustion of glucose, for example, which takes place in our own cells, there is a reaction in which carbon acts as a reducing agent by changing its oxidation state;
* non-oxidizable metals: in this category are phosphorus and sulfur;
* materials that have cellulose: here we can mention paper, wood and fabrics;
* Alkali metals: although a large part of metals can be considered reducing agents, as occurs with iron when oxidized by oxygen, alkali metals stand out for their special action in this context. Some examples are lithium, rubidium, potassium, and sodium;
* sugars: they go through combustion when oxygen oxidizes them to a certain temperature;
* formic acid: also known as methanoic acid, it is an organic acid that has only one carbon atom, which is why it is considered the simplest of its group;
* hydrides: they are binary compounds that result from the union of a chemical element (such as being a metal or a nonmetal) and hydrogen atoms. It should be mentioned that there can be no noble gases in its composition.
During photosynthesis and in the development of printed photographs, among other processes, reducing agents also intervene.