In the volumetric analysis of $HCl$,if we use phenolphthalein as an indicator,which base is unsuitable for titration?

$110 \, mL$ of $0.1 \, N \, HCl$ is titrated with $30 \, mL$ of $0.2 \, N \, NaOH$. The remaining titration is completed by adding $0.25 \, N \, KOH$ solution. What volume of $KOH$ in $mL$ is required?

If $25 \ mL$ of $H_2SO_4$ solution is neutralized by $32.63 \ mL$ of $0.164 \ M \ NaOH$ solution,what is the molarity of the $H_2SO_4$ solution?

The strength of an aqueous solution of $I_2$ can be determined by titrating the solution with a standard solution of:

In the titration of a strong acid and a weak base,the indicator used is:

If soap has a high alkali content,it irritates the skin. How can the amount of excess alkali be determined? What can be the source of excess alkali?