Oxide layer

[Primarygun]

Why does aluminium so readily form an oxide layer on its surface compared with other metals?

What does Iron(II , III) means?

Fe3O4

II= FeO

III=Fe2O3

I recognised that it is the sum of the two oxides, but shouldn't it be the mean of the two oxides?

Also, is the reaction of potassium reaction a displacement reaction?

[budullewraagh]

aluminum is quite an active metal. if you look at the alkali metals, they do the same thing too because oxygen is very electronegative and aluminum has a low ionization energy

[jdurg]

And with the alkali metals, the metal oxide is soluble in water and isn't strongly bound to the metal. Therefore, it will expose more of the metal to reaction. While aluminum is pretty darned reactive, the oxide is NOT soluble in water and it adheres to the metal very strongly, thus protecting it from further reaction.

[budullewraagh]

well, the alkali oxides becomes the hydroxides in water, do they not?

[Primarygun]

In fact, what's a displacement reaction?

It is mainly occured in a solution?

[mak10]

displacement reactions are those where a particular molecule/element in a compound gets displaced by a more reactive molecule/element in that compound, by a reaction. Like when chlorine displaces iodine from KI and forms KCl in a reaction.... since it is more electronegative and thus reactive than iodine. It can occur in solutions as well as in gaseous reactions... i think.

 

-mak10

[Primarygun]

Thank you

[budullewraagh]

speaking of potassium iodide, a better way than using chlorine is to use a powerful oxidizing agent like hydrogen peroxide