$A$ $0.1 \ N$ solution of $Na_2CO_3$ is titrated with $0.1 \ N$ $HCl$ solution. The best indicator to be used is

Which indicator is suitable for the titration of $NaOH$ and oxalic acid?

The best indicator for the detection of the end point in the titration of a strong acid and a weak base is:

The $pH$ range of methyl orange as an indicator is in between:

For which of the following titrations is phenolphthalein the most suitable indicator?

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: