Acid base indicatorOrganic dye in an acid base indicator shows the end point through a visible color changeThe two common examples of acid-base indicators are phenolphthalein and methyl orange.Phenolphthalein signals the end point by a color change from colorless to pink.When it is added to the acidic solution, it shows no colorand pH will be 8.2When it is added to the basic solution, it becomes pink color and pH will be 10Methyl orange indicates the end point by a color change from pink to yellow.When it is added to the acidic solution, it shows pink color and pH will be 3.1When it is added to the basic solution, it shows yellow color and pH will be 4.4
pH scalepH scale is based on the concentration of hydrogen ions in a solution.The pH scale is measured to check whether the substance is acidic or basic.The pH scale ranges from 0 to 14.The strongest acid has a pH value of less than 1 and the weakest acid has a pH value ofis6.The strongest alkali has a pH value of 14 and the weakest alkali has a pH value of 8.Neutral substances such as water have pH value of 7.