Chapter 12, Problem 12.28P

(a)

Interpretation Introduction

Interpretation:

Mass balance for ${\text{CaF}}_2$ in water has to be written.

Concept Introduction:

Mass balance equation represents net quantity of all such species in solution that have specific atoms must remain equal to total quantity of atoms added or delivered to the system initially.

For example, if $0.020\text{ mol}$ of acetic acid has been dissolved in $1\text{ L}$ solvent to form $0.020{\text{ M CH}}_3\text{COOH}$ solution, then after dissolution, amount of unionized and ionized acetic acid must remain equal to $0.020\text{ M}$.

  $0.020\text{ M}=\left[{\text{CH}}_3{\text{COO}}^{-}\right]+\left[{\text{CH}}_3\text{COOH}\right]$

For any systematic equilibrium, there might be more than one mass balance equations unlike charge balance equation. Such equations are governed by possible product species.

(b)

Interpretation Introduction

Interpretation:

Mass balance equation for ${\text{CaF}}_2$ in water when additional species $\text{HF}$ and ${\text{HF}}_2^{-}$ are also formed have to be written.

Concept Introduction:

Refer to part (a).