How does an organic pH indicator works. (illustrate using chemical equations and

mathematical expressions

A pH indicator is a halochromic chemical compound added in small amounts to a solution so the pH (acidity or basicity) of the solution can be determined visually. Hence, a pH indicator is a chemical detector for hydronium ions (H3O+) or hydrogen ions (H+) in the Arrhenius model. A pH of 7 indicates a neutral solution like water. A pH less than 7 indicates an acidic solution and a pH greater than 7 indicates a basic solution. Ultimately, the pH value indicates how much H + has dissociated from molecules within a solution. The lower the pH value, the higher concentration of H + ions in the solution and the stronger the acid. Likewise, the higher the pH value, the lower the concentration of H + ions in the solution and the weaker the acid.