I read from a source that the aqueous solution of ferrous sulfate ($\ce{FeSO4}$) gives an unstable brown compound on treating with $\ce{NaNO2}$ and dilute $\ce{HCl}$. Well, it is quite understandable that it is the $\ce{HNO2}$ formed in situ that further causes the reaction. But what is the reaction and what is that unstable compound formed?
Asked
Active
Viewed 120 times
0
-
2Possible duplicate of What is the Structure of FeSO₄ • NO? – Mithoron May 05 '17 at 18:03
-
1@Mithoron, it is not, cause I didn't know what it was. – Aaron John Sabu May 05 '17 at 18:30
1 Answers
7
Iron(II) reduces nitrite to nitrogen monoxide which forms a brown pentaaquanitrosyliron(II) complex with the iron(II) ions.
$$\ce{NO2^{-} + Fe^{2+} + 2H+ -> NO + Fe^{3+} + H2O}$$
$$\ce{[Fe(H2O)6]^{2+} + NO -> [Fe(H2O)5NO]^{2+} + H2O}$$
Iron(II) can also reduce nitrate to nitrogen monoxide. This is used in the brown ring test to determine the presence of nitrate in aqueous solutions.
aventurin
- 7,200
- 3
- 27
- 38