Answer:
Types of indicators which show if the solution is an acid , alkali or a natural
Step-by-step explanation:
You add one of two drops of the indicator into a solution and then it would be in a scale from red to purple and this is called a PH scale which shows if it's an acid, alkali or a natural solution red being a strong acid with the PH number of one , green being a natural solution with the PH number of 7 and an alkali being purple with the PH number of 14
Hope this helps :)