Chapter 12, Problem 12.37P

(a)

Interpretation Introduction

Interpretation:

Fraction of pyridine found in form of Base and ${\text{BH}}^{+}$ at $\text{pH}$ 4 has to be calculated.

Concept Introduction:

Formula to compute fraction of a base in form of ${\text{BH}}^{+}$ is as follows:

  ${\text{α}}_{{\text{BH}}^{+}}=\frac{\left[{\text{H}}^{+}\right]}{\left[{\text{H}}^{+}\right]+K_{\text{a}}}$

Formula to compute fraction of a base in form of $\text{B}$ is as follows:

  ${\text{α}}_{\text{B}}=\frac{K_{\text{a}}}{\left[{\text{H}}^{+}\right]+K_{\text{a}}}$

Here

$\left[{\text{H}}^{+}\right]$ denotes concentration of $\left[{\text{H}}^{+}\right]$.

$K_{\text{a}}$ denotes ionization constant of acid..

${\text{α}}_{\text{HA}}$ denotes fraction in form of $\text{HA}$.

(b)

Interpretation Introduction

Interpretation:

Fraction of pyridine found in form of base and ${\text{BH}}^{+}$ at $\text{pH}$ 5 has to be calculated.

Concept Introduction:

Refer to part (a).

(c)

Interpretation Introduction

Interpretation:

Fraction of pyridine found in form of base and ${\text{BH}}^{+}$ at $\text{pH}$ 6 has to be calculated.

Concept Introduction:

Refer to part (a).