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Ferrous sulfate and copper sulfate suspension

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AWK:
At pH ~ 9 you will have insoluble iron (II) and copper hydroxides. If they have contact with air (which also contains carbon dioxide), hydrated iron (III) oxide will form very quickly. The basic copper carbonate will be formed slower.

Wanderer0:
thank you for all the answers.
After dissolving the Cu pentahydrate, I am left with Cu2+ and  SO42-
From the ferrous sulphate i have also SO42- and a Fe2+.
Will Fe2+ ions continue binding to SO42- until all are oxidased?
I have never had such a case, and this problem is above my knowledge of the subject.

Any contribution is most welcome

Borek:

--- Quote from: Wanderer0 on March 20, 2019, 10:02:55 PM ---Will Fe2+ ions continue binding to SO42- until all are oxidased?
--- End quote ---

Ions in the solution, after dissociation, are not bound to any specific ion. The only thing that matters is that the solution is electrically neutral, what ions are present doesn't matter.

Ions can react and interact, making complexes or precipitates, but that's not the case of Fe2+ and SO42- (or, rather - complexing properties of SO42- are way too low to matter).

AWK:
Neither in crystals nor in solutions of ionic compounds have covalent bonds between ions. The total formula informs us only about the composition of the stoichiometric unit of the compound.

After graduation, the chemist has intellectual tools to imagine the structure of a not very complicated chemical compound from its total formula (not always correctly, but he knows where to check it), e.g. copper sulfate pentahydrate in the crystal has a structure [Cu(H2O)4]SO4·H2O, and in the solution there are ions [Cu(H2O)6]2+ next to hydrated sulfate ions with undefined stoichiometry of water molecules (and therefore the water is omitted in ions, or it is included in the form of SO42-(aq) and then when balancing chemical reactions we neglect this (aq).

At pH 9, the solution also contains 10,000 times more OH- ions than the H3O+ ions. For both salts, the concentration of hydroxide ions is sufficient to immediately produce Cu(OH)2 (anhydrous) and Fe(OH)2 (hydrated with undefined stoichiometry)

You can find the rest in good textbooks.

Wanderer0:
Borek, AWK; also chenbeier and Mitch:
Thank you very much for help with your responses.
I am not a chemist, (unfortunately), but I am required to reproduce an experiment that requires a chemical formulation.
My interest is in the effect of iron and copper salts on an exposed organic surface, and these observations are in my field of expertise.

However, the presented chemical formulation was unclear to me since it stated that an aqueous solution or a gel (which would be much easier to apply) are required, and that pH which allowed iron and copper to remain stable in the desired form would be from 8,5-10,5. Also, the formulation stated ferrous ion as an active component and given the basic environment, I could not make sense of it since ferric iron would appear very soon, and the observations were to be performed for 12 hours.

I am now wondering about potential pH modifiers.

Once again, thanks.

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