Many chemicals are acidic, neutral or alkaline. We can distinguish one from another using indicators. Acidity and alkalinity are measured on the pH scale.
An indicator A chemical that gives a colour change in acidic, alkaline and neutral solutions. is a chemical that changes colour in acidCorrosive substance which has a pH lower than 7. , alkaline When a base dissolves in water it is an alkali and makes an alkaline solution. and neutralIf a solution is neither acidic nor alkaline it is neutral. solutions. Some common indicators include red litmus paper, blue litmus paper, phenolphthalein, and methyl orange.