Calculate for example the evolution of $pH$ when $20\; mL$ $HCl\; 0.10 M$ are titrated by $NaOH\; 0.10 M$ $x$ is the volume of NaOH which has already been added (in $mL$)
$20\; mL$ $HCl\; 0.10 M$ are titrated by $NaOH\; 0.10 M$
$x$ is the volume of NaOH which has already been added (in $mL$)
