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Is thiocyanate ion a test for ferric ion?

Answer 1

Thiocyanate ion is a test for the ferric ion, #Fe^(3+)#.

Addition of sodium thiocyanate to ferric salts gives the blood-red complex, #[Fe(N=C=S)(OH_2)_5]^(2+)#. I think the ligand binds thru the nitrogen.

And #Co^(2+)# gives a blue complex. This was in fact used as a screening test for the presence of cocaine (i.e. it is used in the field, because it gives a visual determination). Only problem is that such a test for coke is completely unreliable, and a lot of people were wrongly arrested on the basis of this test.

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Answer 2

Jacob Anderson

Yes, thiocyanate ion ((SCN^-)) is a test for ferric ions (Fe^3+). In the presence of ferric ions, thiocyanate forms a blood-red complex (([Fe(SCN)]^{2+})), serving as a qualitative test for the presence of Fe^3+ ions.

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Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.