Question

______ $(\mathrm{AgCl}/{\mathrm{PbCl}}_2)$a white precipitate is soluble in excess of ${\mathrm{NH}}_4\mathrm{OH}$.

Answer 1

Part 1: Observation when Ammonium hydroxide$\left({\mathrm{NH}}_4\mathrm{OH}\right)$is added to Lead salts

1. When Ammonium hydroxide$\left({\mathrm{NH}}_4\mathrm{OH}\right)$ is added to Lead salts, a white precipitate is formed which is insoluble in excess of ${\mathrm{NH}}_4\mathrm{OH}$
2. So, the Lead salts are insoluble in excess of ${\mathrm{NH}}_4\mathrm{OH}$.

Part 2: Observation when Ammonium hydroxide$\left({\mathrm{NH}}_4\mathrm{OH}\right)$is added to Silver salts

1. When Ammonium hydroxide$\left({\mathrm{NH}}_4\mathrm{OH}\right)$ is added to Silver salts, a white precipitate is formed which is soluble in excess of ${\mathrm{NH}}_4\mathrm{OH}$.
2. $$\begin{gathered} \mathrm{AgCl}\left(\mathrm{aq}\right)+2{\mathrm{NH}}_4\mathrm{OH}\left(\mathrm{l}\right)\to 2{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)+\left[\mathrm{Ag}{\left({\mathrm{NH}}_3\right)}_2\right]\mathrm{Cl}\left(\mathrm{aq}\right) \\ \mathrm{Silver}\mathrm{Chloride}+\mathrm{Ammonium}\mathrm{hydroxide}\to \mathrm{water}+\mathrm{Diammine}\mathrm{Silver}\mathrm{Chloride} \end{gathered}$$
3. So, Silver salts are soluble in excess of ${\mathrm{NH}}_4\mathrm{OH}$

So. $\mathrm{AgCl}$ a white precipitate is soluble in excess of ${\mathrm{NH}}_4\mathrm{OH}$.