Question

64. (a) Give a chemical test to distinguish between the following pairs of chemicals:

(1) Lead nitrate solution and Zinc nitrate solution

Answer 1

1. Lead nitrate and Zinc nitrate can be easily distinguished by adding Ammonium hydroxide$\mathit{N}{\mathit{H}}_{\mathbf{4}}\mathit{O}\mathit{H}$.
2. When Ammonium hydroxide is added to Lead nitrate($\mathit{P}\mathit{b}{\mathbf{\left(}\mathit{N}{\mathit{O}}_{\mathbf{3}}\mathbf{\right)}}_{\mathbf{2}}$) forms a white precipitate and is soluble in an excess amount of Ammonium hydroxide solution.
3. While Zinc nitrate($\mathit{Z}\mathit{n}{\mathbf{\left(}\mathit{N}{\mathit{O}}_{\mathbf{3}}\mathbf{\right)}}_{\mathbf{2}}$) also forms a white precipitate with Ammonium hydroxide but it will not dissolve by adding an excess amount of Ammonium hydroxide.
4. Hence by the addition and by testing the solubility with Ammonium hydroxide, Lead nitrate and Zinc nitrate can be easily distinguished.