Chapter 9, Problem 9.84E

Interpretation Introduction

(a)

Interpretation:

The dissociation reactions and $K_a$ expressions for the given weak acids are to be stated.

Concept introduction:

The strength of acids and bases can be determined on the basis of their dissociation reactions and their dissociation constants. Those acids or bases which dissociate almost completely are strong acids or strong bases and those which dissociate to smaller extents are weak or moderately weak acids and weak bases.

Answer to Problem 9.84E

The dissociation reaction for the given weak acid, ${\text{HSe}}^{-}$ is,

${\text{HSe}}^{-}\left(\text{aq}\right)⥄{\text{H}}^{+}\left(\text{aq}\right)+{\text{Se}}^{2-}\left(\text{aq}\right)$

The dissociation constant for the given reaction is,

$K_a=\frac{\left[{\text{H}}^{+}\right]\left[{\text{Se}}^{2-}\right]}{\left[{\text{HSe}}^{-}\right]}$

Explanation of Solution

The dissociation reaction for the given weak acid, ${\text{HSe}}^{-}$ is,

${\text{HSe}}^{-}\left(\text{aq}\right)⥄{\text{H}}^{+}\left(\text{aq}\right)+{\text{Se}}^{2-}\left(\text{aq}\right)$

The dissociation constant for the given reaction is,

$K_a=\frac{\left[{\text{H}}^{+}\right]\left[{\text{Se}}^{2-}\right]}{\left[{\text{HSe}}^{-}\right]}$

The $\left[{\text{H}}^{+}\right]$ and $\left[{\text{Se}}^{2-}\right]$ are the equilibrium concentrations of proton and conjugate base of the given acid respectively and $\left[{\text{HSe}}^{-}\right]$ represents the equilibrium concentration of acid. For weak acids, the values of the concentrations of proton and conjugate base is smaller than that of the concentration of acid, such that the value of $K_a$, that is, the dissociation constant is smaller.

Conclusion

The dissociation reaction for the given weak acid, ${\text{HSe}}^{-}$ is,

${\text{HSe}}^{-}\left(\text{aq}\right)⥄{\text{H}}^{+}\left(\text{aq}\right)+{\text{Se}}^{2-}\left(\text{aq}\right)$

The dissociation constant for the given reaction is,

$K_a=\frac{\left[{\text{H}}^{+}\right]\left[{\text{Se}}^{2-}\right]}{\left[{\text{HSe}}^{-}\right]}$

Interpretation Introduction

(b)

Interpretation:

The dissociation reactions and $K_a$ expressions for the given weak acids are to be stated.

Concept introduction:

The strength of acids and bases can be determined on the basis of their dissociation reactions and their dissociation constants. Those acids or bases which dissociate almost completely are strong acids or strong bases and those which dissociate to smaller extents are weak or moderately weak acids and weak bases.

Answer to Problem 9.84E

The dissociation reaction for the given weak acid, ${\text{H}}_2{\text{BO}}_3^{-}$ (1st $\text{H}$ only) is,

${\text{H}}_2{\text{BO}}_3^{-}\left(\text{aq}\right)⥄{\text{H}}^{+}\left(\text{aq}\right)+{\text{HBO}}_3^{2-}\left(\text{aq}\right)$

The dissociation constant for the given reaction is,

$K_a=\frac{\left[{\text{H}}^{+}\right]\left[{\text{HBO}}_3^{2-}\right]}{\left[{\text{H}}_2{\text{BO}}_3^{-}\right]}$

Explanation of Solution

The dissociation reaction for the given weak acid, ${\text{H}}_2{\text{BO}}_3^{-}$ (1st $\text{H}$ only) is,

${\text{H}}_2{\text{BO}}_3^{-}\left(\text{aq}\right)⥄{\text{H}}^{+}\left(\text{aq}\right)+{\text{HBO}}_3^{2-}\left(\text{aq}\right)$

The dissociation constant for the given reaction is,

$K_a=\frac{\left[{\text{H}}^{+}\right]\left[{\text{HBO}}_3^{2-}\right]}{\left[{\text{H}}_2{\text{BO}}_3^{-}\right]}$

The $\left[{\text{H}}^{+}\right]$ and $\left[{\text{HBO}}_3^{2-}\right]$ are the equilibrium concentrations of proton and conjugate base of the given acid respectively and $\left[{\text{H}}_2{\text{BO}}_3^{-}\right]$ represents the equilibrium concentration of acid. For weak acids, the values of the concentrations of proton and conjugate base is smaller than that of the concentration of acid, such that the value of $K_a$, that is, the dissociation constant is smaller.

Conclusion

The dissociation reaction for the given weak acid, ${\text{H}}_2{\text{BO}}_3^{-}$ (1st $\text{H}$ only) is,

${\text{H}}_2{\text{BO}}_3^{-}\left(\text{aq}\right)⥄{\text{H}}^{+}\left(\text{aq}\right)+{\text{HBO}}_3^{2-}\left(\text{aq}\right)$

The dissociation constant for the given reaction is,

$K_a=\frac{\left[{\text{H}}^{+}\right]\left[{\text{HBO}}_3^{2-}\right]}{\left[{\text{H}}_2{\text{BO}}_3^{-}\right]}$

Interpretation Introduction

(c)

Interpretation:

The dissociation reactions and $K_a$ expressions for the given weak acids are to be stated.

Concept introduction:

The strength of acids and bases can be determined on the basis of their dissociation reactions and their dissociation constants. Those acids or bases which dissociate almost completely are strong acids or strong bases and those which dissociate to smaller extents are weak or moderately weak acids and weak bases.

Answer to Problem 9.84E

The dissociation reaction for the given weak acid, ${\text{HBO}}_3^{2-}$ is,

${\text{HBO}}_3^{2-}\left(\text{aq}\right)⥄{\text{H}}^{+}\left(\text{aq}\right)+{\text{BO}}_3^{3-}\left(\text{aq}\right)$

The dissociation constant for the given reaction is,

$K_a=\frac{\left[{\text{H}}^{+}\right]\left[{\text{BO}}_3^{3-}\right]}{\left[{\text{HBO}}_3^{2-}\right]}$

Explanation of Solution

The dissociation reaction for the given weak acid, ${\text{HBO}}_3^{2-}$ is,

${\text{HBO}}_3^{2-}\left(\text{aq}\right)⥄{\text{H}}^{+}\left(\text{aq}\right)+{\text{BO}}_3^{3-}\left(\text{aq}\right)$

The dissociation constant for the given reaction is,

$K_a=\frac{\left[{\text{H}}^{+}\right]\left[{\text{BO}}_3^{3-}\right]}{\left[{\text{HBO}}_3^{2-}\right]}$

The $\left[{\text{H}}^{+}\right]$ and $\left[{\text{BO}}_3^{3-}\right]$ are the equilibrium concentrations of proton and conjugate base of the given acid respectively and $\left[{\text{HBO}}_3^{2-}\right]$ represents the equilibrium concentration of acid. For weak acids, the values of the concentrations of proton and conjugate base is smaller than that of the concentration of acid, such that the value of $K_a$, that is, the dissociation constant is smaller.

Conclusion

The dissociation reaction for the given weak acid, ${\text{HBO}}_3^{2-}$ is,

${\text{HBO}}_3^{2-}\left(\text{aq}\right)⥄{\text{H}}^{+}\left(\text{aq}\right)+{\text{BO}}_3^{3-}\left(\text{aq}\right)$

The dissociation constant for the given reaction is,

$K_a=\frac{\left[{\text{H}}^{+}\right]\left[{\text{BO}}_3^{3-}\right]}{\left[{\text{HBO}}_3^{2-}\right]}$

Interpretation Introduction

(d)

Interpretation:

The dissociation reactions and $K_a$ expressions for the given weak acids are to be stated.

Concept introduction:

The strength of acids and bases can be determined on the basis of their dissociation reactions and their dissociation constants. Those acids or bases which dissociate almost completely are strong acids or strong bases and those which dissociate to smaller extents are weak or moderately weak acids and weak bases.

Answer to Problem 9.84E

The dissociation reaction for the given weak acid, ${\text{HAsO}}_4^{2-}$ is,

${\text{HAsO}}_4^{2-}\left(\text{aq}\right)⥄{\text{H}}^{+}\left(\text{aq}\right)+{\text{AsO}}_4^{3-}\left(\text{aq}\right)$

The dissociation constant for the given reaction is,

$K_a=\frac{\left[{\text{H}}^{+}\right]\left[{\text{AsO}}_4^{3-}\right]}{\left[{\text{HAsO}}_4^{2-}\right]}$

Explanation of Solution

The dissociation reaction for the given weak acid, ${\text{HAsO}}_4^{2-}$ is,

${\text{HAsO}}_4^{2-}\left(\text{aq}\right)⥄{\text{H}}^{+}\left(\text{aq}\right)+{\text{AsO}}_4^{3-}\left(\text{aq}\right)$

The dissociation constant for the given reaction is,

$K_a=\frac{\left[{\text{H}}^{+}\right]\left[{\text{AsO}}_4^{3-}\right]}{\left[{\text{HAsO}}_4^{2-}\right]}$

The $\left[{\text{H}}^{+}\right]$ and $\left[{\text{AsO}}_4^{3-}\right]$ are the equilibrium concentrations of proton and conjugate base of the given acid respectively and $\left[{\text{HAsO}}_4^{2-}\right]$ represents the equilibrium concentration of acid. For weak acids, the values of the concentrations of proton and conjugate base is smaller than that of the concentration of acid, such that the value of $K_a$, that is, the dissociation constant is smaller.

Conclusion

The dissociation reaction for the given weak acid, ${\text{HAsO}}_4^{2-}$ is,

${\text{HAsO}}_4^{2-}\left(\text{aq}\right)⥄{\text{H}}^{+}\left(\text{aq}\right)+{\text{AsO}}_4^{3-}\left(\text{aq}\right)$

The dissociation constant for the given reaction is,

$K_a=\frac{\left[{\text{H}}^{+}\right]\left[{\text{AsO}}_4^{3-}\right]}{\left[{\text{HAsO}}_4^{2-}\right]}$

Interpretation Introduction

(e)

Interpretation:

The dissociation reactions and $K_a$ expressions for the given weak acids are to be stated.

Concept introduction:

The strength of acids and bases can be determined on the basis of their dissociation reactions and their dissociation constants. Those acids or bases which dissociate almost completely are strong acids or strong bases and those which dissociate to smaller extents are weak or moderately weak acids and weak bases.

Answer to Problem 9.84E

The dissociation reaction for the given weak acid, $\text{HClO}$ is,

$\text{HClO}\left(\text{aq}\right)⥄{\text{H}}^{+}\left(\text{aq}\right)+{\text{ClO}}^{-}\left(\text{aq}\right)$

The dissociation constant for the given reaction is,

$K_a=\frac{\left[{\text{H}}^{+}\right]\left[{\text{ClO}}^{-}\right]}{\left[\text{HClO}\right]}$

Explanation of Solution

The dissociation reaction for the given weak acid, $\text{HClO}$ is,

$\text{HClO}\left(\text{aq}\right)⥄{\text{H}}^{+}\left(\text{aq}\right)+{\text{ClO}}^{-}\left(\text{aq}\right)$

The dissociation constant for the given reaction is,

$K_a=\frac{\left[{\text{H}}^{+}\right]\left[{\text{ClO}}^{-}\right]}{\left[\text{HClO}\right]}$

The $\left[{\text{H}}^{+}\right]$ and $\left[{\text{ClO}}^{-}\right]$ are the equilibrium concentrations of proton and conjugate base of the given acid respectively and $\left[\text{HClO}\right]$ represents the equilibrium concentration of acid. For weak acids, the values of the concentrations of proton and conjugate base is smaller than that of the concentration of acid, such that the value of $K_a$, that is, the dissociation constant is smaller.

Conclusion

The dissociation reaction for the given weak acid, $\text{HClO}$ is,

$\text{HClO}\left(\text{aq}\right)⥄{\text{H}}^{+}\left(\text{aq}\right)+{\text{ClO}}^{-}\left(\text{aq}\right)$

The dissociation constant for the given reaction is,

$K_a=\frac{\left[{\text{H}}^{+}\right]\left[{\text{ClO}}^{-}\right]}{\left[\text{HClO}\right]}$