Section-D: Comprehension Type
Acid-Base titrations are made in presence of acid-base indicators. The acid-base indicators are the substance (weak electrolytes) which furnishes excess of coloured anion or cation in presence of acid or base. Phenolphthalein furnishes more coloured anions in presence of alkali whereas methyl orange furnishes more coloured cations in presence of acid. Phenolphthalein is not a good indicator for weak alkali titrations whereas methyl orange is not a good indicator for weak acid titrations.
Phenolphthalein gives pink colour on addition in