Question

A brown ring appears in the test for

• A. nitrate
• B. nitrite
• C. bromide
• D. iron

Answer 1

Answer: (A)

nitrate

Answer 2

At the junction of salt formation and $FeSO _{4}$ solution with conc. $H _{2} SO _{4}$ a brown ring is obtained $\left( FeSO _{4} \cdot NO \right) .$ $\underset{\text{nitrate salt soluble in water}}{NO _{3}^{-}}+6 FeSO _{4}+3 H _{2} SO _{4} \rightarrow 3 Fe _{2}\left( SO _{4}\right)_{3}$ $FeSO _{4}+ NO \rightarrow \underset{\text{brown ring}}FeSO _{4} \cdot NO$