Question

A compound is soluble in water. If ammonia is added to aqueous solution of the compound, a brown precipitate appears which is soluble in $dil.HCl$. The compound has :

• A. Aluminium
• B. Zinc
• C. Iron
• D. Cadmium

Answer 1

The correct option is C Iron

The compound is $FeC{l}_3$ which is soluble in water and forms brown precipitate of $Fe(OH{)}_3$

$FeC{l}_3\left(aq\right)+3N{H}_{4}OH\left(aq\right)\to Fe(OH{)}_3+3N{H}_{4}Cl$

The brown precipitate again converts into $FeC{l}_3$ on addition of dil $HCl$ which again get solubilized.

$Fe(OH{)}_3+3HCl\to FeC{l}_3+H_{2}O$