# Is it easier to oxidise iron(II) to iron(III) in acidic or alkaline solution? [closed]

Is it easier to oxidise $$\ce{Fe^2+}$$ to $$\ce{Fe^3+}$$ in acidic or alkaline solution?

\begin{align} \ce{Fe &-> Fe^2+(aq) -> Fe^3+(aq)}\\ \ce{Fe &-> Fe(OH)2 -> Fe(OH)3} \end{align}

In my textbook it is written that as soon as $$\ce{Fe^{2+}}$$ changes to $$\ce{Fe^{3+}}$$, it acquires $$\ce{OH-}$$ to form $$\ce{Fe(OH)3}$$. This promotes oxidation of $$\ce{Fe^{2+}}$$ changes to $$\ce{Fe^{3+}}$$. I don't quite get this why precipitate formation speeds up the reaction?

• You said it yourself: the reactions are different. – Ivan Neretin Jul 18 '20 at 10:31
• @user Look, your question has been edited using standardized notations and formatting. Please make sure you use it as an example in your edits. If you have questions regarding formatting, visit this page, this page and this one. – andselisk Jul 18 '20 at 11:04
• The experience shows that a crystal or a solution containing the ion $\ce{Fe^{2+}}$ may be useful for a couple of hours without being significantly oxidized. On the contrary, a precipitate of $\ce{Fe(OH)_2}$ starts being oxidized by oxygen from the air in less than one minute. – Maurice Jul 18 '20 at 11:31
• @user Please note, it is $\ce{Fe^2+}$ and not $\ce{Fe^{+2}}$. See: chemistry.stackexchange.com/questions/24769/… – Nilay Ghosh Jul 18 '20 at 11:48
• – Nilay Ghosh Jul 18 '20 at 11:50