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On making this up, it is of course a light green. By adding Conc sulfuric acid it should go clear. But my 2 litres of freshly made up Iron II Sulfate, is not going clear. Is the chemical too old?

there is no need to use conc sulfuric acid, 2M will do. It is not suppose to go clear just lighter.

Thank you Jazz

My Iron (11) Sulfate - FeSO4 has gone BROWN...Can I add something to it to clear it up or Should I dispose and make up a New Batch????

I make it up fresh and make up just enough to cover the prac activity. I usually weigh out lots of 7g and keep it in glass vials, so all I need to do is make them up to 250ml for a 0.1m solution.

splash of 1 M sulfuric acid

Iron II Sulfate, should be made up fresh every time, for it to work. Put a Fe nail (NEW) of course into the solution, this helps it not going to Iron III a little slower. After a week it goes down the sink, with plenty of water.

I always use ferrous ammonium sulphate - this doesn't oxidise in solution to the brown ferric species. Stores longer and doesn't need to be made up immediately before use.

Thank You

I bought ammonium ferrous sulfate to use in our cation identification prac and have just made a 0.1M solution. After making it I realised that I hadn't checked how to make it and that maybe it needed sulfuric acid in it like ferrous sulfate does. According to "The Laboratory" it doesn't though. Does anyone else use this chemical, do you use sulfuric when making it up and does it work ok in all of the different tests for Fe2+?
I see that David Peterson posted that he does (I think it was his post that got me to buy it in the first place) but I'm not sure if he is still on here.
Thanks in advance.

CSIS page 135 tells us, " Slightly toxic if ingested. acidified solutions are stabel to oxidation. Iron (II) Compounds are susceptible to oxidation in air. Dilute solutions (0.1M) are used to test cations."

Labbie wrote: ↑04 Mar 2010, 08:05 On making this up, it is of course a light green.

An old post but I normally make this up with tap water as recommended in the Labbies manual for most solutions except Silver Nitrate .
Although the solid is a light green colour , the solution always quickly turns brown during stirring .

Well this time I used distilled water ( it's a new thing , I am using it for all solutions now ) .....and surprise , it stayed a light green colour . I'm curious to see how long it stays that way .
I showed my Chem teacher , he was as surprised as me , he's been served brown Iron II Sulfate Solution for over 30 years


Always learning and discovering .

Iron II Sulfate, should be made up fresh every time, for it to work. Put a Fe nail (NEW) of course into the solution, this helps it not going to Iron III a little slower. The little nail really does work.

Labbie wrote: ↑06 Aug 2019, 14:01 Put a Fe nail (NEW) of course into the solution, this helps it not going to Iron III a little slower. The little nail really does work.

Might give that a go Labbie

Last a few more days, then without one.

I have tried & Tried to undo this, but it will not let me. The Minute I did it, I realised. So Sorry