Question

Distinguish by adding sodium hydroxide solution to calcium salt and lead salt.

Answer 1

On adding sodium hydroxide and ammonium hydroxide solution to calcium salt and lead salt, following reactions will takes place.

Salts	When adding small amount of NaOH	When adding excess of NaOH
Calcium salt	A white precipitate forms. $$\begin{gathered} {\mathrm{CaCl}}_2\left(\mathrm{s}\right)+2\mathrm{NaOH}\left(\mathrm{aq}\right)\to \mathrm{Ca}{\left(\mathrm{OH}\right)}_2\left(\mathrm{s}\right)+2\mathrm{NaCl}\left(\mathrm{s}\right) \\ \mathrm{Calcium}\mathrm{chloride}\mathrm{Sodium}\mathrm{hydroxide}\mathrm{Calcium}\mathrm{hydroxide}\mathrm{Sodium}\mathrm{chloride} \end{gathered}$$	White precipitate sparangily soluble in excess NaOH.
Lead salt	White precipitate forms. $$\begin{gathered} \mathrm{Pb}{\left({\mathrm{NO}}_3\right)}_2\left(\mathrm{s}\right)+2\mathrm{NaOH}\left(\mathrm{s}\right)\to \mathrm{Pb}{\left(\mathrm{OH}\right)}_2\left(\mathrm{s}\right)+2{\mathrm{NaNO}}_3\left(\mathrm{aq}\right) \\ \mathrm{Lead}\mathrm{nitrate}\mathrm{Sodium}\mathrm{hydroxide}\mathrm{Lead}\mathrm{hydroxide}\mathrm{Sodium}\mathrm{nitrate} \end{gathered}$$	White precipitate soluble in excess NaOH