Chapter 12, Problem 12.2P

(a)

Interpretation Introduction

Interpretation:

At $\text{3}\text{.50}\text{pH}$ degree of dissociation $\text{α}{}_{{\text{Y}}^{\text{4-}}}$ should be calculated.

Concept Information:

Degree of dissociation:

The ratio of mole of reactant that underwent to dissociating to mole of initial reactant is known as degree of dissociation.

In EDTA the degree of dissociation is,

$\text{α}{}_{{\text{Y}}^{\text{4-}}}\text{=}\frac{{\text{[Y}}^{\text{4-}}\text{]}}{{\text{[H}}_{\text{6}}{\text{Y}}^{\text{2+}}{\text{]+[H}}_{\text{5}}{\text{Y}}^{\text{+}}{\text{]+[H}}_{\text{4}}{\text{Y]+[H}}_{\text{3}}{\text{Y}}^{\text{-}}{\text{]+[H}}_{\text{2}}{\text{Y}}^{\text{2-}}{\text{]+[H}}_{\text{3}}{\text{Y}}^{\text{3-}}{\text{]+[Y}}^{\text{4-}}\text{]}}$

The degree of dissociation of $\text{EDTA}$ is the ration of all free $\text{EDTA}$ in the form of ${\text{Y}}^{\text{4-}}$

$\text{α}{}_{{\text{Y}}^{\text{4-}}}\text{=}\frac{{\text{[Y}}^{\text{4-}}\text{]}}{\text{[EDTA]}}$

(b)

Interpretation Introduction

Interpretation:

At $\text{10}\text{.50}\text{pH}$ degree of dissociation $\text{α}{}_{{\text{Y}}^{\text{4-}}}$ should be calculated.

Concept Information:

Degree of dissociation:

The ratio of mole of reactant that underwent to dissociating to mole of initial reactant is known as degree of dissociation.

In EDTA the degree of dissociation is,

$\text{α}{}_{{\text{Y}}^{\text{4-}}}\text{=}\frac{{\text{[Y}}^{\text{4-}}\text{]}}{{\text{[H}}_{\text{6}}{\text{Y}}^{\text{2+}}{\text{]+[H}}_{\text{5}}{\text{Y}}^{\text{+}}{\text{]+[H}}_{\text{4}}{\text{Y]+[H}}_{\text{3}}{\text{Y}}^{\text{-}}{\text{]+[H}}_{\text{2}}{\text{Y}}^{\text{2-}}{\text{]+[H}}_{\text{3}}{\text{Y}}^{\text{3-}}{\text{]+[Y}}^{\text{4-}}\text{]}}$

The degree of dissociation of $\text{EDTA}$ is the ration of all free $\text{EDTA}$ in the form of ${\text{Y}}^{\text{4-}}$

$\text{α}{}_{{\text{Y}}^{\text{4-}}}\text{=}\frac{{\text{[Y}}^{\text{4-}}\text{]}}{\text{[EDTA]}}$