Chapter 18, Problem 62E

Interpretation Introduction

(a)

Interpretation:

Whether the reaction ${\text{Cu}}^{2+}({\text{aq) + H}}_2\text{S(satd aq) }\to$ proceeds to a significant extent in the forward direction should be predicted and the products should be determined.

Concept introduction:

Major objective of qualitative cation analysis is identifying the cations present in a mixture. In qualitative cation analysis, cations are categorized into 5 groups depending on the solubilities of their compounds. Pb²⁺, Hg₂²⁺, Ag⁺ belong to the first group which form insoluble chlorides when HCl(aq) is added. When the remaining solution is added with H₂S in an acidic medium(0.3 M HCl), a group of sulfides precipitate. The remaining solution from this is next treated with H₂S in a buffer mixture of NH₃ and NH₄+ ions which then gives a mixture of insoluble hydroxides and sulfides. Filtrate of above reaction mixture is then treated with CO₃^2-. This yields carbonate precipitates of cations. In the final solution, all the water soluble cations include.

Interpretation Introduction

(b)

Interpretation:

Whether the reaction ${\text{Mg}}^{2+}({\text{aq) + H}}_2\text{S(satd aq) }\stackrel{0.3\text{ M HCl}}{\to }$ proceeds to a significant extent in the forward direction should be predicted and the products should be determined.

Concept introduction:

Major objective of qualitative cation analysis is identifying the cations present in a mixture. In qualitative cation analysis, cations are categorized into 5 groups depending on the solubilities of their compounds. Pb²⁺, Hg₂²⁺, Ag⁺ belong to the first group which form insoluble chlorides when HCl(aq) is added. When the remaining solution is added with H₂S in an acidic medium (0.3 M HCl), a group of sulfides precipitate. The remaining solution from this is next treated with H₂S in a buffer mixture of NH₃ and NH₄₊ ions which then gives a mixture of insoluble hydroxides and sulfides. Filtrate of above reaction mixture is then treated with CO₃^2-. This yield carbonate precipitates of cations. In the final solution, all the water soluble cations include.

Interpretation Introduction

(c)

Interpretation:

Whether the reaction $\text{PbS}(s\text{) + HCl(0}\text{.3 M) }\to$ proceeds to a significant extent in the forward direction should be predicted and the products should be determined.

Concept introduction:

Major objective of qualitative cation analysis is identifying the cations present in a mixture. In qualitative cation analysis, cations are categorized into 5 groups depending on the solubilities of their compounds. Pb²⁺, Hg₂²⁺, Ag⁺ belong to the first group which form insoluble chlorides when HCl(aq) is added. When the remaining solution is added with H₂S in an acidic medium (0.3 M HCl), a group of sulfides precipitate. The remaining solution from this is next treated with H₂S in a buffer mixture of NH₃ and NH₄+ ions which then gives a mixture of insoluble hydroxides and sulfides. Filtrate of above reaction mixture is then treated with CO₃^2-. This yield carbonate precipitates of cations. The final solution includes all the water soluble cations.

Interpretation Introduction

(d)

Interpretation:

Whether the reaction $\text{ZnS}(s{\text{) + HNO}}_3\text{(aq) }\to$ proceeds to a significant extent in the forward direction should be predicted and the products should be determined.

Concept introduction:

Major objective of qualitative cation analysis is identifying the cations present in a mixture. In qualitative cation analysis, cations are categorized into 5 groups depending on the solubilities of their compounds. Pb²⁺, Hg₂²⁺, Ag⁺ belong to the first group which form insoluble chlorides when HCl(aq) is added. When the remaining solution is added with H₂S in an acidic medium (0.3 M HCl), a group of sulfides precipitate. The remaining solution from this is next treated with H₂S in a buffer mixture of NH₃ and NH₄+ ions which then gives a mixture of insoluble hydroxides and sulfides. Filtrate of above reaction mixture is then treated with CO₃^2-. This yield carbonate precipitates of cations. In the final solution, all the water soluble cations include.