Congo red indicator
Hydrochloric acid
Sodium hydroxide
So how indicator use? It weaknesses acids and change slightly alkaline conditions, the weak bases change under slightly acidic.
pH what is that? pH is the measure in activity hydrogen ion. Solutions with pH greater than 7 are known as basic or alkaline.
Why acid-base indicator?
acid-base indicator weak base and acid but a indicator can make change color from acid to alkaline by a hydrogen ion concentration. Color change interval is also well known as pH range.
Congo red Indicator: Indicator for pH levels
Color change on a pH range: 3.0-5.0
Color of acid: blue
Color of base: red