Hi,

In a water that contains manganese, iron and ammonium, I wondered what interaction they have with each other in terms of oxidation? I understand that they all oxidise but which element would oxidise first? Is it as simple as looking at the element and the shells to see which would lose an electron first?

Thanks

Regards,

Andre

4 hours ago, Andre_212 said:

In a water that contains manganese, iron and ammonium, I wondered what interaction they have with each other in terms of oxidation? I understand that they all oxidise but which element would oxidise first? Is it as simple as looking at the element and the shells to see which would lose an electron first?

Ammonium is not element, but compound. Maybe you meant Aluminium instead? It would make more sense in context of your question.

https://en.wikipedia.org/wiki/Ammonia_solution

"In aqueous solution, ammonia deprotonates a small fraction of the water to give ammonium and hydroxide according to the following equilibrium:"

NH₃ + H₂O <-> NH₄⁺ + OH^-

Look up "Activity Series of the Elements"

2 hours ago, Sensei said:

Ammonium is not element, but compound. Maybe you meant Aluminium instead? It would make more sense in context of your question.

 

Both could make sense in terms of water quality.

What gets oxidised first depends on how oxidised they already are.

On 7/31/2017 at 4:39 PM, Andre_212 said:

Hi,

In a water that contains manganese, iron and ammonium, I wondered what interaction they have with each other in terms of oxidation? I understand that they all oxidise but which element would oxidise first? Is it as simple as looking at the element and the shells to see which would lose an electron first?

Thanks

Regards,

Andre

Hello Andre!

The manganese would convert into a black, chunky, powdery, sometimes pastlike oxide known as manganese dioxide (MnO2). The iron would form a red, metallic, flaky oxide which will quickly fall of the metal exposing it to further oxidation. Eventually the iron will all be turned into this iron oxide (rust). The aluminum needn't get that far. It doesn't need water to oxidize, it forms an oxide in air. It forms a very thin and very tough ceramic layering of oxide that is only about one bond thick. It prevents further oxidation so well that you can keep it on the water for billions of years without much of a change. However, pure aluminum oxide is usually a powder. It is a ceramic material with very good heat resistance. To completely oxidize the aluminum, you need to make atom-thick shavings out of the aluminum rod which is essentially impossible. Bottom line: iron would rust away, manganese would convert into a loose chunky black pigment, and the aluminum would go through no visible reaction. Thanks for asking!

-RadioChemist