A $10\mathrm{.}00-$mL sample of vinegar $($acetic acid, $C{H}_3\frac{C}{O}OH)$ was pipetted into a flask, two drops of phenolphthalein indicator were added, and the acid was titrated with $0\mathrm{.}1008$MNaOH.

$($a$)$ If $25\mathrm{.}82mL$ of the base was required for the titration, what was the molar concentration of acetic acid in the sample?

$($b$)$ What is the $pH$ at the endpoint? $)=(1\mathrm{.}8{10}^{-5}$

$($c$)$ If the density of the pipetted acetic acid solution was $1\mathrm{.}004\frac{g}{m}L,$ what was the percentage of acetic acid in the sample? $($molar mass $=60\mathrm{.}05\frac{g}{m}ol)$