Question

(vii) Which of the following is an example of adsorption
indicators?
(a) Eosin
(b) Phenolphthalein
(c) Methyl red
(d)
Ninhydrin​

Answer 1

Eosin is an example of Absorption Indicator

Explanation:

Which of the following is an example of adsorption  indicators?

(a) Eosin- Correct answer

(b) Phenolphthalein

(c) Methyl red

(d)  Ninhydrin

• To detect the endpoints of precipitation titration, the phenomenon of absorption is used.
• Absorption indicators are the chemicals placed in a solution that can indicate the excess of the ions by changing the color of the precipitate.
• In precipitation titration, dye-like stuff is used such as eosin, fluorescein, alizarin red, etc.
• When the endpoint of the titration is reached anions of the indicator absorb on precipitate and the color of the precipitate changes.