[danago]

Hi.
Somebody who is currently doing highschool chemistry came across a question he was not sure about, which i am also not sure about. The question simply wants an example of a substance used as an analytical primary standard in titrations, green in colour, which contains a transition metal.

Now i can think of heaps of transition metal-containing substances which are green (salts of chromium, nickel etc.), however am not too sure which one would make a good primary standard. I know there are certain conditions to which a substance must pertain if it is to be an effective standard, but is there a specific example that really stands out and is perhaps used on a fairly common basis?

Thanks,
Daniel.

[UG]

I think it might be ammonium iron(II) sulfate, something like (NH₄)₂Fe(SO₄)₂.6H₂O

[danago]

Ah ok thanks, that sounds about right!