Question

$F{e}^{2+}$ gives a green coloured precipitate with:

• A. ammonium molybdate
• B. potassium permanganate
• C. sodium silicate
• D. sodium hydroxide

Answer 1

Answer: (D)

sodium hydroxide

A solution of a Iron salt (Iron ammonium sulphate solution for $F{e}^{2+}$) mixed with an equal amount of another solution, gives a physical change, usually a colour change due to a precipitation of the iron insoluble compound or formation of a complex since iron is a transitional metal. The green / cyan ppt, insoluble in excess formed with sodium hydroxide and carbonate is already a good indication of the presence of $F{e}^{2+}$.