acid + base + indicator expplain it why?
Answers
Answer:
Acid-base indicators are chemicals used to determine whether an aqueous solution is acidic, neutral, or alkaline. Because acidity and alkalinity relate to pH, they may also be known as pH indicators. Examples of acid-base indicators include litmus paper, phenolphthalein, and red cabbage juice.
Answer:
Acid - Base Indicators and Titrations
Acid - Base indicators (also known as pH indicators) are substances which change colour with pH. They are usually weak acids or bases, which when dissolved in water dissociate slightly and form ions.
Consider an indicator which is a weak acid, with the formula HIn. At equilibrium, the following equilibrium equation is established with its conjugate base:
The acid and its conjugate base have different colours. At low pH values the concentration of H3O+ is high and so the equilibrium position lies to the left. The equilibrium solution has the colour A. At high pH values, the concentration of H3O+ is low - the equilibrium position thus lies to the right and the equilibrium solution has colour B.
Phenolphthalein is an example of an indicator which establishes this type of equilibrium in aqueous solution:
colourless (Acid) pink (Base)