Chapter 2, Problem 54P

(a)

Interpretation Introduction

Interpretation:

The predominant form of the compound $C{H}_{3}COOH$ that exist at $pH=3,6,10,14$ has to be drawn.

Concept introduction:

If a base receives one proton, then the formed species is a conjugate acid whereas an acid lose one proton, then the formed species is a conjugated base.

If an acid lose one proton, then the formed species is a conjugated base. Weak base forms stronger conjugated acid.

Henderson-Hasselbalch equation explains the relationship between $pH$ of solution and $p{K}_a$ of acid. For a dissociation of acid $\left(HA\right)$ in aqueous solution,

$HA+H_{2}O\underset{}{\overset{}{\rightleftharpoons }}{H}_3{O}^{+}+A^{-}$

$p{K}_a=pH+\log \frac{\left[HA\right]}{\left[A^{-}\right]}$

During a dissociation of acid in aqueous solution,

• If $pH=p{K}_a$, the concentration of compound in its acidic and basic form is equal.
• If $pH<p{K}_a$, the compound exist in its acidic form.
• If $pH>p{K}_a$, the compound exist in its basic form.

(b)

Interpretation Introduction

Interpretation: The predominant form of the compound $C{H}_{3}C{H}_2\stackrel{+}{N}{H}_3$ that exist at $pH=3,6,10,14$ has to be drawn.

Concept introduction:

If a base receives one proton, then the formed species is a conjugate acid whereas an acid lose one proton, then the formed species is a conjugated base.

If an acid lose one proton, then the formed species is a conjugated base. Weak base forms stronger conjugated acid.

Henderson-Hasselbalch equation explains the relationship between $pH$ of solution and $p{K}_a$ of acid. For a dissociation of acid $\left(HA\right)$ in aqueous solution,

$HA+H_{2}O\underset{}{\overset{}{\rightleftharpoons }}{H}_3{O}^{+}+A^{-}$

$p{K}_a=pH+\log \frac{\left[HA\right]}{\left[A^{-}\right]}$

During a dissociation of acid in aqueous solution,

• If $pH=p{K}_a$, the concentration of compound in its acidic and basic form is equal.
• If $pH<p{K}_a$, the compound exist in its acidic form.
• If $pH>p{K}_a$, the compound exist in its basic form.

(c)

Interpretation Introduction

Interpretation:

The predominant form of the compound $C{F}_{3}C{H}_{2}OH$ that exist at $pH=3,6,10,14$ has to be drawn.

Concept introduction:

If a base receives one proton, then the formed species is a conjugate acid whereas an acid lose one proton, then the formed species is a conjugated base.

If an acid lose one proton, then the formed species is a conjugated base. Weak base forms stronger conjugated acid.

Henderson-Hasselbalch equation explains the relationship between $pH$ of solution and $p{K}_a$ of acid. For a dissociation of acid $\left(HA\right)$ in aqueous solution,

$HA+H_{2}O\underset{}{\overset{}{\rightleftharpoons }}{H}_3{O}^{+}+A^{-}$

$p{K}_a=pH+\log \frac{\left[HA\right]}{\left[A^{-}\right]}$

During a dissociation of acid in aqueous solution,

• If $pH=p{K}_a$, the concentration of compound in its acidic and basic form is equal.
• If $pH<p{K}_a$, the compound exist in its acidic form.
• If $pH>p{K}_a$, the compound exist in its basic form.