The different colours of litmus in acidic,neutral and basic solutions are,respectively.

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

For an acid indicator with $K_{in} = 1.0 \times 10^{-5}$, the color change occurs when the concentration of the indicator is $1 \times 10^{-3} \ M$. Find the $pH$ at which the color change occurs.

Methyl orange is an indicator in acid-alkali titration. It gives

The $pH$ indicators are

Which indicator can be used in the titration of a strong acid and a strong base?