Chapter 11, Problem 122CP

a.

Interpretation Introduction

Interpretation: The concentration of ${\text{F}}^{-}$ ion in the given solution needs to be determined.

Concept Introduction:The measurement of energy per unit charge which is available from the redox reactions to carry out the reaction is said to be cell potential.

b.

Interpretation Introduction

Interpretation: The concentration of ${\text{F}}^{-}$ ion should be calculated for part (a) when pH = 9.00 and the percent error introduced in the concentration of ${\text{F}}^{-}$ needs to be determined by neglecting the hydroxide interference.

Concept Introduction: The measurement of energy per unit charge which is available from the redox reactions to carry out the reaction is said to be cell potential.

c.

Interpretation Introduction

Interpretation: The value of maximum pH for concentration of ${\text{F}}^{-}$ ion in (b) part needs to be determined so that $\frac{\left[{\text{F}}^{\text{-}}\right]}{\text{k}\left[{\text{OH}}^{\text{-}}\right]}\text{ = 50}$ .

Concept Introduction:pH stands for "potential of hydrogen", it is a measure of alkalinity or acidity of water-soluble substances. pH number ranges from 0 to 14.

• pH is a logarithmic scale which specify the acidity or basicity of the solution.

  $pH=-\log [H^{+}]$

d.

Interpretation Introduction

Interpretation: The minimum pH at which 99% of the fluoride is present as ${\text{F}}^{-}$ and 1% as $\text{HF}$ needs to be determined.

Concept Introduction:pH stands for "potential of hydrogen", it is a measure of alkalinity or acidity of water-soluble substances. pH number ranges from 0 to 14.

• pH is a logarithmic scale which specify the acidity or basicity of the solution.

  $pH=-\log [H^{+}]$

e.

Interpretation Introduction

Interpretation: The reason for addition of buffering agents to solution containing fluoride before the measurements via fluoride-selective electrode needs to be explained.

Concept Introduction:Buffering agents are used that results in minimizing the amount of ions that are acting as preventing interface.