I'm looking over the experiment questions we'll be doing before I do it.
Solution A is Fe compound dissolved in water.
It says, "Add 1cm depth of solution A into test tube. Add NaOH(aq)"
Record your observations over the next five minutes.
I'm thinking that maybe the compound is FeSO4, (Is this safe to use in schools?)
Then I'm thinking, if you add NaOH, Fe(OH)2 solid precipitate will form.
This is a green precipitate.
But because it says over 5 minutes, will a rusty brown surface on the precipitate form as Fe2+ is oxidsed to Fe3+ in the presence of air?