Identify the colour change observed when $NaCl$ solution is titrated against $AgNO_3$ solution using fluorescein as an indicator.

$10.0 \, mL$ of $Na_{2}CO_{3}$ solution is titrated against $0.2 \, M \, HCl$ solution. The following titre values were obtained in $5$ readings.
$4.8 \, mL, 4.9 \, mL, 5.0 \, mL, 5.0 \, mL$ and $5.0 \, mL$
Based on these readings,and convention of titrimetric estimation,the concentration of $Na_{2}CO_{3}$ solution is .... $mM$.
(Round off to the nearest integer)

While titrating a dilute $HCl$ solution with an aqueous $NaOH$ solution,which of the following will not be required?

Why in the redox titration of $KMnO_4$ vs oxalic acid,do we heat the oxalic acid solution before starting the titration?

In the titration of $KMnO_{4}$ with $C_{2}O_{4}^{2-}$,which temperature range is not proper? Why?

During the estimation of oxalic acid $V/S$ $KMnO_4$,the self-indicator is: