In the detection of nitrogen of an organic compound by Lassaigne's test, Prussian blue colour is obtained . This is due to the formation of which of the following complexes ?

Options

A. `Fe_(2) [Fe(CN)_(6)]`
B. `Fe_(4)[Fe(CN)_(6)]_(3)`
C. `Fe_(3)[Fe(CN)_(6)]_(4)`
D. `Na_(4)[Fe(CN)_(6)]`

Answer

B

Explanation

In Lassaigne.s test for detection of nitrogen in orgainc compounds Prussian blue colour is obtained due to the formation of
iron (III) hexacyanoferrate (II) complex. The reaction is follows :
`6CN^(-) Fe^(2+) to underset("Hexacyanoferrate")([Fe(CN)_(6)]^(4-))`
`3[ Fe(CN)_(6)]^(4-)overset(xH_(2)O)tounderset(("Prussian blue")) underset("Iron (III) hexacyanoferrate (II)")([Fe_(4) (CN)_(6) ]_(3)*xH_(2)O)`