Chapter 19, Problem 19.147P

(a)

Interpretation Introduction

Interpretation:

Picture that represents the solution just after the solid $\text{MZ}$ is stirred thoroughly in distilled water has to be identified.

Concept introduction:

Solubility:

Solubility is a chemical property of a given substance i.e. solute to dissolve in solvent.

For slightly soluble salts the solute dissolves in little amount in solvent to give respective ions and there is always an equilibrium between the ions of the salt and the unionized molecules.

(b)

Interpretation Introduction

Interpretation:

Value of ${\text{K}}_{\text{sp}}$ for $\text{MZ}$ has to be calculated as the ion concentration in each sphere is $\text{2}\text{.5}\times {10}^{-6}$ M.

Concept introduction:

Solubility:

Solubility is defined as the maximum amount of the solute that can be dissolved in the solvent at equilibrium.

Solubility product constant:

Solubility product constant is defined for equilibrium between solids and its respective ions in the solution. Generally, solubility product refers only to insoluble or slightly soluble ionic substances that make equilibrium in water.

It is defined as the product of concentration of ions of a sparingly soluble salt in its saturated solution at ${25}^{\text{o}}\text{C}$. The concentration terms are raised to the coefficients of their respective ions. It is denoted by ${\text{K}}_{\text{sp}}$.

This value indicates the degree of dissociation of a compound in water. More the value of ${\text{K}}_{\text{sp}}$ more is the solubility of the compound.

Considering an equilibrium of salt ${\text{A}}_{\text{x}}{\text{B}}_{\text{y}}$ with its respective ions in solution and thus ${\text{K}}_{\text{sp}}$ is calculated.

  ${\text{A}}_{\text{x}}{\text{B}}_{\text{y}}\stackrel{}{\rightleftarrows }{\text{xA}}^{\text{y+}}+{\text{yB}}^{\text{x}}{}^{\text{-}}$

  ${\text{K}}_{\text{sp}}\text{=}{\left[{\text{xA}}^{\text{y+}}\right]}^{\text{x}}{\left[{\text{yB}}^{\text{x-}}\right]}^{\text{y}}$

(c)

Interpretation Introduction

Interpretation:

Figure representing the solution after addition of ${\text{Na}}_2\text{Z}$ (aq) has to be identified.

Concept introduction:

Common ion effect:

Suppression of ionization of a weak electrolyte by the addition of a strong electrolyte in the same solution and one ion must be common in between both the weak and strong electrolyte.

 Le Chatelier’s principle:

When a system in equilibrium is subjected to any external disturbance like change of pressure, volume, temperature etc…Then the system acts in a way to prevent that change. This is called Le Chatelier’s principle.

(d)

Interpretation Introduction

Interpretation:

The scene that interprets the situation after lowering of $\text{pH}$ and when ${\text{Z}}^{\text{2-}}$ is given as ${\text{CO}}_3^{2-}$ has to be determined.

Concept introduction:

Chemical Equilibrium:

Chemical equilibrium is the process where the rate of forward reaction and the rate of backward reaction are equal.

Le Chatelier’s principle:

When a system in equilibrium is subjected to any external disturbance like change of pressure, volume, temperature etc… Then the system acts in a way to prevent that change. This is called Le Chatelier’s principle.