Tests to Distinguish Iron(II) and Iron(III) ions

The presence of Fe²⁺ ion and Fe³⁺ ion in a salt can be confirmed by using solution of potassium hexacyanoferrate (II), solution of potassium hexacyanoferrate (III) and potassium thiocyanate.
Table below shows the observation of the tests.

Reagent	Observation	Ion presents
Solution of potassium hexacyanoferrate (II)	Light blue precipitate	Fe²⁺
Solution of potassium hexacyanoferrate (II)	Dark Blue precipitate	Fe³⁺
Solution of potassium hexacyanoferrate (III)	Dark blue precipitate	Fe²⁺
Solution of potassium hexacyanoferrate (III)	Greenish brown solution	Fe³⁺
Potassium thiocyanate	Pinkish solution	Fe²⁺
Potassium thiocyanate	Blood red solution	Fe³⁺