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

Assertion : $Sb_2S_3$ is not soluble in yellow ammonium sulphide. Reason : The common ion effect due to $S^{2-}$ ions reduces the solubility of $Sb_2S_3$.

What concentration of $Ac^{-}$ ions will reduce $H_3O^{+}$ ion concentration to $2 \times 10^{-4} \ M$ in a $0.40 \ M$ solution of $HAc$ (in $M$)? Given $K_a (HAc) = 1.8 \times 10^{-5}$.

Explain the common ion effect on the solubility of salts.

$H_2S$ gas,when passed through a solution containing $HCl$,precipitates the cations of group $II$ of qualitative analysis but not those belonging to the fourth group. This is because:

In which of the following,the solubility of $AgCl$ will be minimum?