Cation ( A ) + K 4 [ Fe ( CN ) 6 ] ⟶ B (Chocolate brown ppt.) When cation C react with thiosulphate ion then initially violet colour complex is formed which turns into light green coloured solutio

Question

Cation ( A ) + K 4 ​ [ Fe ( CN ) 6 ​ ] ⟶ B (Chocolate brown ppt.) When cation C react with thiosulphate ion then initially violet colour complex is formed which turns into light green coloured solution. Ιdentify formula of (D) :

TestHub · Accepted Answer

The reaction of cation (A) with K₄[Fe(CN)₆] to form a chocolate brown precipitate (B) indicates the presence of Fe³⁺ ions. This is a characteristic test for ferric ions, forming ferric ferrocyanide.

Reaction:

$4 Fe^{3 +} + 3 K_{4} [Fe (CN)_{6}] ⟶ Fe_{4} [Fe (CN)_{6}]_{3} ↓ (C h oco l a t e b ro w n ppt .) + 12 K^{+}$

Therefore, the chocolate brown precipitate (B) is $Fe_{4} [Fe (CN)_{6}]_{3}$ .

The final answer is $Fe_{4} [Fe (CN)_{6}]_{3}$ .

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