A $30mL$ sample of $0\mathrm{.}2M$ histidine in its fully protonated form is titrated with $0\mathrm{.}1$MNaOH until the $pH$ of the solution reaches

The titration curve is shown in the image. Complete the $x-$axis by indicating the volume of NaOH solution required to reach

the indicated positions of the titration curve. The $p{K}_a$ values for histidine are $1\mathrm{.}82,6\mathrm{.}00,$ and $9\mathrm{.}17.$

Answer Bank

Incorrect

What volume of $0\mathrm{.}1$MNaOH is required to raise the $pH$ to the $\frac{?}{pI}$ of histidine?

volume of $0\mathrm{.}1$MNaOH :

$120$

Calculate the $pH$ of the solution after $33mL$ of $0\mathrm{.}1$MNaOH has been added to the sample.

Note: When the $pH$ of the solution is near one of the $p{K}_a$ values, assume that the Henderson$-$Hasselbalch equation holds for the

two major species present at that $pH.$

$pH$:$3\mathrm{.}8$

Incorrect