Question

The blue compound formed in the positive test for nitrogen with lassaigne solution of an organic compound is.

• A. $Na_{4}\lbrack Fe(CN)_{5}(NOS)\rbrack$
• B. $Na_{3}\lbrack Fe(CN)_{6}\rbrack$
• C. $Fe(CN)_{3}$
• D. $Fe_{4}\lbrack Fe(CN)_{6}\rbrack_{3}$

Answer 1

Answer: (D)

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

Answer 2

: Ferriferrocyanide is the blue complex formed by sodium ferrocyanide and NaCN.

$3Na_{4}\lbrack Fe(CN)_{6}\rbrack + 2Fe_{2}(SO_{4})_{3} \rightarrow \underset{Blue}{Fe_{4}\lbrack Fe(CN)_{6}}\rbrack_{3}$

$+ 6Na_{2}SO_{4}$