Question

In any ferric salt, on adding potassium ferrocyanide, a prussian blue colour is obtained, which is.

• A. $K_{3}Fe(CN)_{6}$
• B. $KFe\left\lbrack Fe(CN)_{6} \right\rbrack$
• C. $FeSO_{4}.Fe(CN)_{6}$
• D. $Fe_{4}\left\lbrack Fe(CN)_{6} \right\rbrack_{3}$

Answer 1

Answer: (D)

$Fe_{4}\left\lbrack Fe(CN)_{6} \right\rbrack_{3}$

Answer 2

$\underset{\text{pot. ferrocyanide}}{3K_{4}\lbrack Fe(CN)_{6}\rbrack + 4FeCl_{3}} \rightarrow \underset{(\text{Prussion blue})}{\underset{(\text{Ferri ferrocynide})}{Fe_{4}\lbrack Fe(CN)_{6}\rbrack_{3} + 12KCl}}$