Which reagent can be used to separate $Fe(OH)_3$ from $Al(OH)_3$?

When $HCl$ gas is passed through a saturated solution of $BaCl_2$,a white precipitate is obtained. This is due to:

The solubility product of $AgCl$ is $8 \times 10^{-6}$. Find its new solubility in the presence of $0.01 \ M \ NaCl$.

$0.01 \ mol$ of a weak acid $HA$ $(K_{a} = 2.0 \times 10^{-6})$ is dissolved in $1.0 \ L$ of $0.1 \ M$ $HCl$ solution. The degree of dissociation of $HA$ is ............. $\times 10^{-5}$ (Round off to the Nearest Integer). [Neglect volume change on adding $HA$. Assume degree of dissociation $<< 1$]

Assertion : In the third group of qualitative analysis,$NH_4Cl$ is added to $NH_4OH$ medium.
Reason : This is to convert the ions of group into their respective chlorides.

Explain the effect on the resulting solution when $0.05 \ M$ acetate ion is added to a $0.05 \ M$ acetic acid solution.