Why FeSO4 turns yellow when kept in open?
The solution is as follows:
Iron (Fe) is a transition metal that shows variable oxidation state. Thus, when FeSO4, in which Fe is in +2 oxidation state is exposed to atmosphere, it oxidises from Fe2+ to Fe3+ and the colour of Fe in +3 state is yellow.
The reaction is:
Fe2+ Fe3+ + e-
Iron (Fe) is a transition metal that shows variable oxidation state. Thus, when FeSO4, in which Fe is in +2 oxidation state is exposed to atmosphere, it oxidises from Fe2+ to Fe3+ and the colour of Fe in +3 state is yellow.
The reaction is:
Fe2+ Fe3+ + e-
