detecting Fe(II) ions (1 Viewer)

[MissGeorgie]

anyone know how to detect Fe (2+) ions in a solution?

 

[Tommy_Lamp]

add OH- (NaOH)
if it turns green, then brown its Fe2+
if it turns brown straight away, its Fe3+

 

[MissGeorgie]

thanks muchly

 

[~*HSC 4 life*~]

who thinks learning all these tests for ions is a bitch?

*raises own hand*

 

[Tommy_Lamp]

not rly that hard, just spend one day going over them

 

[xiao1985]

maybe add SCN-... if turn red then Fe 2+ present...

 

[Tommy_Lamp]

yer maybe u can do that, i just have two flowcharts, one for anions and one for cations so ive memorised that

 

[CM_Tutor]

maybe add SCN-... if turn red then Fe 2+ present...

Fe²⁺ does not turn red with SCN^- ions - this is a test for Fe³⁺ only. Fe²⁺ is colourless in the presence of SCN^- ions.

Standard detections of Fe²⁺:

1. Prove that iron(II) or iron(III) is present (say by hydroxide precipitation).

2. Distinguish between iron(II) and iron(III) by tests such as:

iron(II) decolourises purple acidified permanaganate solution, whereas iron(III) does not.

iron(III) forms a blood red solution of FeSCN²⁺ with thiocyanate solution, whereas iron(II) remains colourless.

iron(II) forms a pink / red solution with 2,2'-bipyridine in ethanol, whereas iron(III) remains colourless.

iron(II) forms a deep blue solution ('Prussian Blue' = Fe[Fe(CN)₆]^-) with hexacyanoferrate(III), [Fe(CN)₆]^3-, whereas iron(III) remains colourless.

iron(III) forms a deep blue solution ('Prussian Blue' = Fe[Fe(CN)₆]^-) with hexacyanoferrate(II), [Fe(CN)₆]^4-, whereas iron(II) remains colourless.