Which indicator is most suitable for the titration of $0.1 \, N \, Na_2CO_3$ solution with $0.1 \, N \, HCl$?

Indicator for the titration of $HCl$ and $Na_2CO_3$ would be

Which indicator is used for the titration of $CH_3COOH$ and $NaOH$?

The pink color of phenolphthalein in an alkaline medium is due to:

Starch can be used as an indicator for the detection of traces of

The rapid change of $pH$ near the stoichiometric point of an acid-base titration is the basis of indicator detection. The $pH$ of the solution is related to the ratio of the concentrations of the conjugate acid $(HIn)$ and base $(In^{-})$ forms of the indicator by the expression: