Question

Give the differences between double salts and coordination compounds.

Hint:

To test the difference in a lab: Mohr's salt will give a positive test for Fe²⁺ ions, but Potassium ferrocyanide will not give a test for Fe²⁺ ions because the iron is locked inside the coordination sphere [Fe(CN)₆]⁴⁻.

Answer 1

Concept: Both double salts and coordination compounds (complexes) are formed by the combination of two or more stable compounds. However, they behave very differently when dissolved in water.
The primary difference lies in their dissociation behavior in aqueous solution. A double salt dissociates completely into its individual ions, whereas a coordination compound retains its identity and does not dissociate into its constituent ions.
[h] |p0.8cm|p5cm|p5cm| S.No & Double Salts & Coordination Compounds
1 & Dissociate into simple ions completely when dissolved in water. & Do not dissociate into simple ions completely; the complex ion remains intact.
2 & They lose their identity in aqueous solution. & They retain their identity in aqueous solution.
3 & They contain only ionic bonds. & They contain coordinate covalent bonds along with ionic/covalent bonds.
4 & Their properties are the same as those of their constituent ions. & Their properties are entirely different from those of their constituent atoms/ions.
5 & Example: Mohr's Salt, FeSO₄ · (NH₄)₂SO₄ · 6H₂O & Example: Potassium ferrocyanide, K₄[Fe(CN)₆]