Chapter 24, Problem 3ASA

A $\text{0}\text{.3012}\text{g}$ sample of an unknown monoprotic acid requires $\text{24}\text{.13}\text{mL}$ of $\text{0}\text{.0944}\text{M}\text{NaOH}$ for neutralization to a phenolphthalein end point. There are $\text{0}\text{.32}\text{mL}$ of $\text{0}\text{.0997}\text{M}\text{HCl}$ used for back titration.

a. How many moles of ${\text{OH}}^{-}$ are used? How many moles of ${\text{H}}^{\text{+}}$ from $\text{HCl}$?

_______moles ${\text{OH}}^{-}$ ________moles ${\text{H}}^{\text{+}}$

b. How many moles of ${\text{H}}^{\text{+}}$ are there in the solid acid? (Use Eq.5.)

____________ moles ${\text{H}}^{\text{+}}$ in solid

c. What is the molar mass of the unknown acid? (Use Eq.4.)

____________ g/mol