[sharbeldam]

There is this supplement called " spatone " which is basically water with Fe+2.
How do they get it? im sure matallic iron should not dissolve in water if its not acidic etc, but i still wonder how do they get that water with the ions, the source must be Fe(s).

In another experiment that Im doing to check for how fast iron gets oxidized, we put a rod of iron in solution that contains K3Fe(CN)6 (that kinda acts as an indicator), but for that compound to react with the iron, iron needs to becomes Fe+2 first which is very confusing to me.
How does Iron becomes Fe+2 in that solution?

[Hunter2]

Do you know rusting of iron. Iron ist also an inoble metal, Fe => Fe2+ + 2 e-, E0 = -0,44 V. Together with oxygen it will be dissolved in water. But it takes some time.

[sharbeldam]

I understand what you are saying, but what im asking isnt related to rust, im just talking about being dissolved, so basically the reaction you typed, it has a negative value, so it shouldnt be spontaneous, or it can happen very slow, so if we put a rod of iron in the water, it will become Fe+2 very slowly?

[Hunter2]

Correct, but in nature iron dont appear as a metal. So rivers and lakes with high iron content came from iron compounds  already containing iron Ions. Metallic iron is man made.

[Aldebaran]

Regarding your comment about the standard electrode potential being negative and therefore not spontaneous: notice that the equilibrium is written as a reduction of the 2+ ion . If instead you start with metallic iron the value for the oxidation reaction would be reversed thus + 0.44 v. This supports our every day experience that metallic iron in the presence of oxygen and water rusts (oxidises) . Iron oxides can react with acids and form various salts one of which is iron(II) sulfate which I believe is what is present in “spatone”.

[sharbeldam]

I understand, thank you both, but to sum it up fully, i dont want to talk about the reaction with oxygen at all. You say metallic iron needs to react with acids to form Fe+2. but my question is why not just put it in water, since it is spontaneous, it should " DISSOLVE " into Fe+2 which is in that supplement too, is it because the reaction is very very slow in water relative to the reaction in acid?

[Hunter2]

It will be stopped, because hydroxide is formed. Fe + 2 H2O => Fe(OH)2 +H2

[sharbeldam]

Its Fe(OH)2 Which is basically Fe+2 as well, why cant it keep forming that hydroxide until it vanishes?

[Hunter2]

The soloubility is poor, it will coat the iron and the reaction will stop.

[Enthalpy]

[...] water with Fe+2.[...]

Positive ions are always accompanied by negative ones. Some description may mention only Fe²⁺, but the composition is a neutral salt like FeSO₄ for instance. Whether a salt is soluble in water depends on both ions - really.

Does water corrode metallic iron? This depends fully on the alloy and on the water composition. Distilled water, rainwater, tap water, seawater, including the amount of dissolved air, differ completely for that. The detailed alloy composition too, which changes the corrosion from small colour change to complete destruction of the object. Pure iron is very seldom used, typically in relays or electromagnets, elsewhere it's cast iron or steel, where the alloy elements even in small amount change radically the corrosion behaviour.

[sharbeldam]

May I ask you, why did you say " does water corrode iron " instead of " does water dissolve iron ", like I know iron doesn't dissolve like salt obviously, but my original question was Does water dissolve iron (Fe(s) + H2O ---> Fe+2 ) ofcourse accompanying with hydroxide ions or others as you said.
I got my answer from the other guy that it's very very slow, so it releases only a bit of Fe+2 ions when put in water, and i get that you agree with him ,but you are just saying the speed of dissolution depends on the type of water and iron, yea?

[Enthalpy]

Corrosion speed is extremely variable and difficult to predict under natural conditions. Some hand heaters use iron corrosion and the reaction lasts few minutes. But the Titanic is still there.

[pcm81]

I am either stupid or am completely missing the point of this thread.

The original question is: "Does metallic iron dissolve in water?". The answer is: No. Ionic form of iron as is present in iron oxide is able to be dissolved in water because it is a polar molecule; however metallic iron still has the electrons in its conduction shell present and is neutral charge, hence not soluble in polar solvent like water. Metallic iron placed in water will oxidize and become ionic iron, which will dissolve in water but at that point it is no longer metallic iron.

[Hunter2]

This is valid to all metals. They have to be oxidised to be an ion and get be dissolved. For some it goes spontaneous like sodium. Others like gold it never happend. Its matter of redoxpotential against hydrogen. Iron is not noble so it will react with water and get dissolved.

[pcm81]

This is valid to all metals. They have to be oxidised to be an ion and get be dissolved. For some it goes spontaneous like sodium. Others like gold it never happend. Its matter of redoxpotential against hydrogen. Iron is not noble so it will react with water and get dissolved.

Correct. But it will, at that point, be ionic iron not metallic iron.