The Student Room Group

It says "over 5 minutes"

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?
Reply 1
Original post by ILoveUSA
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?


Fe2+ tends to get oxidised in air. but since you are yet to do the experiment, i suppose you take note carefully within that five minutes and report what you see rather than what you expect.

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