Question

What do you observe when Ammonium hydroxide is added to Calcium nitrate and Zinc sulfate?

Answer 1

Part-1 Calcium nitrate when reacts with Ammonium hydroxide

• Calcium nitrate (Ca(NO₃)₂ when reacts with Ammonium hydroxide (NH₄OH), no precipitate formation occurs,
• When an excess of Ammonium hydroxide is added, it still doesn't react.
• It happens because the concentration of OH^- ions produced by the ionization of Ammonium hydroxide is very low so it can't precipitate in the hydroxide of calcium.
• $$\begin{gathered} \mathrm{Ca}{\left({\mathrm{NO}}_3\right)}_2\left(\mathrm{aq}\right)+{\mathrm{NH}}_4\mathrm{OH}\left(\mathrm{aq}\right)\to \mathrm{No}\mathrm{reaction} \\ \left(\mathrm{Calcium}\mathrm{nitrate}\right)\left(\mathrm{Ammonium}\mathrm{hydroxide}\right) \end{gathered}$$

Part-2 Zinc sulphate when reacts with Ammonium hydroxide

• When Ammonium hydroxide reacts with Zinc sulphate (ZnSO₄) a white gelatinous precipitate is formed.
• The precipitated form is soluble in excess of Ammonium hydroxide
• $$\begin{gathered} {\mathrm{ZnSO}}_4{\left(\mathrm{aq}\right)}^{}+2{\mathrm{NH}}_4\mathrm{OH}\underset{}{\left(\mathrm{aq}\right)\to }\mathrm{Zn}{\left(\mathrm{OH}\right)}_2\left(\mathrm{s}\right)+{\left({\mathrm{NH}}_4\right)}_2{\mathrm{SO}}_4\left(\mathrm{aq}\right) \\ \left(\mathrm{Zinc}\mathrm{sulphate}\right)\left(\mathrm{Ammonium}\mathrm{hydroxide}\right)\left(\mathrm{Zinc}\mathrm{hydroxide}\right)\left(\mathrm{Ammonium}\mathrm{sulphate}\right) \\ \left(\mathrm{White}\mathrm{gelatinous}\mathrm{ppt}\right) \end{gathered}$$