Indicators are weak acids or bases that exhibit a color change as hydrogen ion concentration in a solution varies or as a solution's pH changes.
In the water, the indicators gently separate to produce ions.
The three examples of indicators are
- Litmus: It is one of the naturally occurring chemical indicators. It is naturally obtained from lichens. It is usually found in form of paper strips. Paler strips are of 2 colors red and blue. Acids change the blue paler to red color whereas the base changes red paper to blue color. Some solutions don't give any color with litmus paper because they are neutral
- Turmeric: it is a type of natural indicator. It is used in our daily life while preparing food. Turmeric gives a yellow color when the acidic medium is the ent brownish-red red color when the basic medium is present. This effect of turmeric is due to a yellow pigment present in it known as curcumin.
- Vanilla extract: It is a type of olfactory indicator. It works by changing the smell when reacted. It gives a pungent smell when reacted with acid. But when the base is added to this extract the reaction is odorless. This is due to certain chemicals present in it.