Chapter 5, Problem 30E

Interpretation Introduction

(a)

Interpretation:

The net ionic equation for the precipitation of ${\left({\text{NH}}_{\text{4}}\right)}_{\text{2}}{\text{HPO}}_{\text{4}}(\text{s})$ should be given.

Concept introduction:

According to the Le Chatelier’s principle, a change in one of the variables that describe a system at equilibrium produces a shift in the position of the equilibrium that counteracts the effect of this change.

Usually, diprotic and polyprotic acid dissociation is undergoes through several equilibrium steps.

Interpretation Introduction

(b)

Interpretation:

The net ionic equation for the precipitation of ${\text{NH}}_{\text{4}}{\text{NO}}_2$ should be given.

Concept introduction:

According to the Le Chatelier’s principle, a change in one of the variables that describe a system at equilibrium produces a shift in the position of the equilibrium that counteracts the effect of this change.

Usually, diprotic and polyprotic acid dissociation is undergoes through several equilibrium steps.

Interpretation Introduction

(c)

Interpretation:

The net ionic equation for the precipitation of ${\left({\text{NH}}_{\text{4}}\right)}_2{\text{SO}}_{\text{4}}$ should be given.

Concept introduction:

Follow the lower-numbered guideline when two guidelines are in conflict. This leads to the correct prediction in most cases.

1. Salts of group 1 cations (with some exceptions for Li⁺) and the NH₄+ cation are soluble.
2. Nitrates, acetates, and perchlorates are soluble.
3. Salts of silver, lead, and mercury (I) are insoluble.
4. Chlorides, bromides, and iodides are soluble
5. Carbonates, phosphates, sulfides, oxides, and hydroxides are insoluble (sulfides of group 2 cations and hydroxides of Ca²⁺, Sr²⁺, and Ba²+ are slightly soluble).
6. Sulfates are soluble except for those of calcium, strontium, and barium.

There are only two possibilities. Either some cation−anion combination leads to an insoluble solid—a precipitate—or no such combination is possible, or there is no reaction at all.