Question

Explain why an aqueous solution of potassium hexacyanidoferrate(II) does not give the test of ferrous ion.

Answer 1

Potassium hexacyanidoferrate(II) is a complex compound that does not release free ferrous ions in water. When dissolved, the Fe²⁺ remains trapped within the stable [Fe(CN)₆]⁴⁻ complex ion due to strong coordinate covalent bonds. Since chemical tests require free Fe²⁺ ions to react, the solution fails to show a positive result.