Question

$F{e}^{3+}$ cations on additions of excess $NaOH$, the precipitate is .............. colored.

• A. green
• B. dark brown
• C. yellow
• D. white

Answer 1

The correct option is B dark brown

Iron belongs to group 3 cations. Cations of this group do not react either with dilute hydrochloric acid, or with hydrogen sulphide in dilute mineral acid medium. However they form precipitates with ammonium sulphide in neutral or ammoniacal medium. When a sample containing $F{e}^{3+}$ ions is treated with excess $NaOH,F{e}^{3+}$ precipitates as a brown colored precipitate.