Description of experiment
Below follows a plain text transcript of the selected experiment.
Needed compounds:
-----------------
sulphuric acid : H2SO4
sodium nitrite : NaNO2
hydrochloric acid : HCl
ferric chloride : FeCl3 . 6H2O
copper sulfate penta hydrate : CuSO4 . 5H2O
Class:
------
elem=Cu,Fe
coordination
redox
Summary:
--------
Nitrous acid (or its decomposition product) forms a dark brown coordination
complex with ferric ions. With copper (II) also a coordination complex is
formed. In relatively strongly acidic environments, these coordination
complexes are destroyed/not formed.
Description:
------------
Sequence 1:
-----------
Add a solution of copper sulfate to a solution of sodium nitrite: Formation of
an intensely colored brownish green compound (a coordination complex of nitrite
and copper?).
Add some sulphuric acid (appr. 1 mol/l): Liquid becomes light blue. The gas
mixture above the liquid becomes light brown.
Add a solution of ferric chloride, acidified with HCl, such that it remains
clear: No visible reaction.
Sequence 2:
-----------
Add a solution of ferric chloride to a solution of sodium nitrite: Formation of
a dark brown compound. The gas mixture above the liquid becomes light brown.
Add some sulphuric acid (appr. 1 mol/l): Liquid becomes light yellow. The
gas mixture above the liquid remains light brown.