Question

What do you mean by the double salts and coordination compounds?

Answer 1

An addition or molecular compound which dissociates into its constituents ions when dissolved in water, is known as double salt. For example,

K₂SO₄.Al₂ (SO₄)₃.24H₂O aq)→ 2K+ (aq) +4SO₄^2- (aq) +2Al³⁺(aq)

Potash alum (double salt) 

Any addition or molecular compound which does not lose its identity in aqueous solution i.e. does not dissociates into its constituent ions. Is known as a coordination compound.For example,

K₄ [Fe(CN)₆] (aq)→ 4 K⁺ (aq) + [Fe(CN)₆ ]^4-(aq)

(Potassium Ferro cyanide)