Description of experiment
Below follows a plain text transcript of the selected experiment.
Needed compounds:
-----------------
hydrogen peroxide : H2O2
ferric ammonium sulfate hydrate : Fe NH4 (SO4)2 . 12H2O
ferrous ammonium sulfate hexa hydrate : Fe (NH4)2 (SO4)2 . 6H2O
Class:
------
elem=Fe,O
coordination
redox
Summary:
--------
Ferrous ions react with H2O2. At low pH, the H2O2 oxidizes the ferrous ions
to ferric ions. At near neutral pH, a complex reaction occurs, the ferrous
ions are converted to some complex with the H2O2.
Ferric ions do not react with H2O2.
Description:
------------
Sequence 1:
-----------
Dissolve some ferric ammonium sulfate in water: The liquid is yellow/brown and
a little turbid, due to hydrolysis.
Add a few drops of H2O2 (10% by weight): No visible changes.
Sequence 2:
-----------
Dissolve some ferrous ammonium sulfate in water: The liquid is almost colorless
and clear.
Add a few drops of H2O2 (10%): The liquid becomes red/brown and remains clear.
Besides this, the liquid starts bubbling slowly.
Heat the clear red/brown liquid: The evolution of gas becomes much faster. At
a certain point the liquid becomes turbid and orange/brown. The precipitate
probably is ferric hydroxide.