Question

$Fe(OH{)}_3$ can be separated from $Al(OH{)}_3$ by addition of?

• A. $dil.HCl$
• B. $NaCl$ solution
• C. $NaOH$ solution
• D. $N{H}_{4}Cl$ and $N{H}_{4}OH$

Answer 1

Answer: (C)

$NaOH$ solution

$Fe(OH{)}_3$ can be separated from $Al(OH{)}_3$ by addition of NaOH solution.
Only $Al(OH{)}_3$ is soluble in excess of NaOH followed by boiling to form sodium meta-aluminate while $Fe(OH{)}_3$ is insoluble.
$Al(OH{)}_3+NaOH\to Na[Al{O}_2]+2H_{2}O$