Chapter 4, Problem 4.75P

Interpretation Introduction

Interpretation:

The mass percent of benzoic acid when $0.3471\text{g}$ a sample of a mixture of oxalic acid, and benzoic acid is treated with $100.0\text{ mL}$ of $0.1000M\text{ NaOH}$ and the excess $\text{NaOH}$ is titrated with $20.00\text{ mL}$ of $0.2000M\text{ HCl}$ is to be calculated.

Concept introduction:

Strong acids and strong bases are the substance that dissociates completely into its ions when dissolved in the solution. They dissociate completely in water to release ${\text{H}}^{+}$ ions and ${\text{OH}}^{-}$ ions.

Weak acids and weak bases are the substance that does not dissociate completely into its ions when dissolved in the solution. They dissociate partially in water to release ${\text{H}}^{+}$ ions and ${\text{OH}}^{-}$ ions.

Benzoic acid $\left({\text{HC}}_7{\text{H}}_5{\text{O}}_2\right)$, oxalic acid $\left({\text{H}}_{\text{2}}{\text{C}}_{\text{2}}{\text{O}}_4\right)$, and hydrochloric acid $\left(\text{HCl}\right)$ are an acid and sodium hydroxide $\left(\text{NaOH}\right)$ is a strong base.

Sodium hydroxide $\left(\text{NaOH}\right)$ and hydrochloric acid $\left(\text{HCl}\right)$ both dissociate completely into their ions. Benzoic acid $\left({\text{HC}}_7{\text{H}}_5{\text{O}}_2\right)$ and oxalic acid $\left({\text{H}}_{\text{2}}{\text{C}}_{\text{2}}{\text{O}}_4\right)$ do not dissociate completely into their ions

The molecular equation for the acid-base reaction is:

$\begin{array}{l}\text{HCl}\left(aq\right)+\text{NaOH}\left(aq\right)\to \text{NaCl}\left(aq\right)+{\text{H}}_2\text{O}\left(l\right)\\ 2\text{NaOH}\left(aq\right)+{\text{H}}_{\text{2}}{\text{C}}_{\text{2}}{\text{O}}_4\left(aq\right)\to {\text{Na}}_{\text{2}}{\text{C}}_{\text{2}}{\text{O}}_4\left(aq\right)+2{\text{H}}_2\text{O}\left(l\right)\\ \text{NaOH}\left(aq\right)+{\text{HC}}_7{\text{H}}_5{\text{O}}_2\left(aq\right)\to {\text{NaC}}_7{\text{H}}_5{\text{O}}_2\left(aq\right)+{\text{H}}_2\text{O}\left(l\right)\end{array}$