[Rhienne]

What would be the color changes involved in the following reactions?:

ammonium(II) sulphate + oxalic acid -> iron(II) oxalate + ammonium hydrogensulphate

iron(II) oxalate + hydrogen peroxide + potassium oxalate -> potassium trioxalatoferrate(III) + iron(III) hydroxide

iron(III)hydroxide + oxalic acid -> potassium trioxalatoferrate(III)

[Alberto_Kravina]

ammonium(II) sulphate + oxalic acid -> iron(II) oxalate + ammonium hydrogensulphate

Where's iron on the left side?

[Albert]

I think Rhienne forgot to write iron. It's ferrous ammonium sulphate, in my opinion.

[Will]

iron(III) hydroxide

My book says there is no such thing as Fe(OH)₃, it says that Fe₂O₃ (redish/brown rust colour) is produced, when, for example, OH^- is added to Fe³⁺_(aq).
I did a search on google for Fe(OH)3 and 21,800,000 results were found. Is my book wrong? Should I take legal action? lol

If I had the chemicals required to do these reactions I would do them as that is the best way to check for colour changes.
I know that ferrous ammonium sulphate is green and I think potassium trioxalatoferrate(III) is as well.
Which compounds in particular do you not know the colour of, as I think you'll probably know what hydrogen peroxide etc. looks like?

[Albert]

To quote my General Chemistry book: 'however, Ferric hydroxide is an hydrated ferric oxide. This so-called ferric hydroxide acts like a base.'

That's it. 

Maybe it's something like H₂CO₃. however, the colour is the same for both. That's for sure. 

[Will]

Thanks Albert, you're right- my book says its hydrated Fe₂O₃- i.e. Fe₂O₃.xH₂O. When x is 3 it is equivalent (hypothetically) to 2Fe(OH)₃.

the colour is the same for both. That's for sure.

Yup, coincidentally a very rusty colour.