The P Block Elements - Result Question 17
####17. Brown ring test is used to detect
(a) Iodine
(b) Nitrate
(c) Iron
(d) Bromide
[1994]
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Solution:
- (b) Brown ring test is done for the confirmation of $NO_3^{-}$ions.
$ \begin{aligned} & NaNO_3(aq)+H_2 SO_4(aq) \\ & \longrightarrow NaHSO_4(aq)+HNO_3(aq) \\ & 6 FeSO_4+2 HNO_3+3 H_2 SO_4 \\ & \longrightarrow 3 Fe_2(SO_4)_3+2 NO+4 H_2 O \\ & FeSO_4+NO \longrightarrow \underset{\text{ Ferrous nitroso-sulphate }}{[Fe(NO)] SO_4} \\ & \text{ (Brown ring) } \end{aligned} $
