Doxa: Iron

Not going to lie: I feel like a kid in a candy store now that I am accessing

all kinds of resources for Chemistry thanks to AI. This morning, decided

to go to another language for redox reactions: German. It is no secret that

Germany has a very strong Chemistry-based idustrial capacity. Wanted to see

how this is taught.

Below:

Oxidation numbers and redox reactions

1) Oxidation numbers:

At After each oxidation and reduction, electrons are displaced. You are switching from one element to another. The change is evident in the elements by a change in their electrical charge. In the case of very In many simple chemical processes, we have such redox systems. Above all, however, such shifts take place in the more complicated reactions – and this can be seen in the setting up of the equations. Since electrons, atoms or molecules are no more can be lost, they always have to be restored somewhere in the equation. and this makes it easier to find the right coefficients considerable.

At real ion reactions, the oxidation numbers can be easily determined. They correspond to the charges of the individual ions. In Magnesium chloride MgCl2 is the magnesium is doubly positively charged, it has the oxidation number +2; the chlorine is simply negatively charged, it has the Oxidation number -1.

Now However, not all chemical reactions are really ion reactions. Many of them follow different rules – but this does not interfere with this Context: You can pretend that all molecules in equations consist of Ions.

In order that chemical reality is not properly depicted, it makes it easier to However, the equation writing is considerable.

For instance the water molecule is not ionized, yet it can be mentally divided into two positively charged hydrogen ions and a double Break down negatively charged oxygen ion:

2 H⁺ and O^2-

Herefrom you can already deduce the first rule:

When writing equations using the oxidation numbers it is always assumed that hydrogen in compounds has the oxidation number +1, oxygen in compounds has oxidation number -2.

Thereby there are immediately some different oxidation numbers, considering that a molecule must appear neutral on the outside.

The The formula of hydrochloric acid is HCl. Since H is mentally decomposed of the molecule according to the above rule H⁺, there is still a Chlorine only Cl^-. Chlorine is therefore always simply negative in chlorides loaded. The same applies to all elements of halogens (fluorine, chlorine, bromine, iodine, astatine).

So It is also possible to determine the oxidation number of the iron in the ferric chloride FeCl₂. There are two negative chloride ions here two positive charges of iron, i.e. Fe²⁺. Iron has thus the oxidation number +2 in the present ferric chloride.

It However, there is another ferric chloride that has the formula FeCl₃. According to the above example, the iron in this compound must oxidation number +3.

All The compounds mentioned so far could be regarded as true ionic compounds. In order not to come into conflict with these "real" ions, the oxidation numbers are not written in the upper right corner after the symbol, as usual with real ion charges, but vertically via the icon.

After The same principle can be used to give different simple molecules their Assign oxidation numbers.

Elements which are not in combination, but are "elemental" (pure ferrous metal, gold, etc.) By definition, they have an oxidation number of 0. The elemental gases that occur in diatomic form (H₂, O₂, N₂, etc.), are assigned the oxidation number 0.

After In this system, the first equations can be solved.

By the Introduction of chlorine gas into ferrous (II) chloride solution is formed Ferrous (III) chloride.

One clearly shows that the two elemental chlorine atoms with the oxidation number o into two negatively charged chloride ions with the oxidation number -1. In other words, they each took up one electron.

Every Chlorine atom has taken an electron from one

, because the iron dives on the right side of the equation

, so this has lost an electron, since it has become one oxidation state more positive.

There two electrons have been absorbed by the chlorine, there are also two electrons. electrons have been released from the iron; but since each Fe has only one electron to the 2 Fe must have been involved in the reaction.

The So the equation must be: