Chapter 17, Problem 17.117SP

Interpretation Introduction

Interpretation:

The major components present at indicated points in titration curve have to be identified also the ${\text{pK}}_{\text{a1}}\text{and}{\text{pK}}_{\text{a2}}$ values of acids has to be calculated.

Concept introduction:

Acid dissociation constant ${\text{K}}_{\text{a}}$ represents how strong the acid is in a solution. ${\text{pK}}_{\text{a}}$ is defined as negative logarithm of acid dissociation constant(${\text{K}}_{\text{a}}$). 

  $p{K}_a=-\log K_a$

The strength of acid decreases as the value of $p{K}_a$ increases

$p{K}_a$ represents the chance of losing proton from a compound.

Henderson-Hasselbalch equation

$\text{pKa}\text{=}\text{pH}\text{+}\text{log}\frac{\left[\text{HA}\right]}{\left[{\text{A}}^{\text{-}}\right]}$

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,

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

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

Titration is a process where a known concentrated solution is used for determining the concentration of an unknown solution. The known concentrated solution is called the titrant, while the unknown concentrated solution is called the analyte.

The equivalence point is a point in a titration where the amount of standard solution added is sufficient to neutralize the unknown solution completely. At this point, the total number of moles of standard solution (titrant) is equal to the number of moles of an unknown solution (analyte).