The prussian blue colour obtained in the Lassaigne's test for nitrogen is due to formation of:

Question

The prussian blue colour obtained in the Lassaigne's test for nitrogen is due to formation of: (A) Iron (II) hexa cyano ferrate (II) (B) Iron(III) hexa cyano ferrate (II) (C) Iron (III) hexa cyano ferrate (III) (D) Iron (II) hexa cyano ferrate (III)

Tardigrade Admin · Accepted Answer

In Lassaigne's test for nitrogen in sodium extract, add fresh and saturated solution of

F e S O_{4}

followed by

N a O H

. Now boil and cool the content. Then, add dil

H_{2} S O_{4}

and

F e C l_{3}

solution. Formation of Prussian blue precipitate shows the presence of nitrogen.

F e S O_{4} + 2 N a O H \to F e (O H)_{2} ↓ + N a_{2} S O_{4}

F e (O H)_{2} + From sodium extract 6 N a CN \to N a_{4} [F e (CN)_{6}] + 2 N a O H

2 N a_{4} [F e (CN)_{6}] + 4 F e C l_{3} \to Iron (III) hexa cyano ferrate (II) F e_{4} [F e (CN)_{6}]_{3} + 12 N a C

Q. The prussian blue colour obtained in the Lassaigne's test for nitrogen is due to formation of:

Iron $(II)$ hexa cyano ferrate $(II)$

Iron $(III)$ hexa cyano ferrate $(II)$

Iron $(III)$ hexa cyano ferrate $(III)$

Iron $(II)$ hexa cyano ferrate $(III)$