Question

An organic dye, cousins used to detect the endpoint of precipitation titration by the process of

• A. absorption
• B. adsorption
• C. chemical reaction
• D. none of the above

Answer 1

Answer: (B)

adsorption

An organic dye, cosine used to detect the endpoint of precipitation titration by adsorption, is called an adsorption indicator. This is also called Argentometry titration.

Argentometry is a type of titration involving the silver(I) ion. Typically, it is used to determine the amount of chloride present in a sample. The sample solution is titrated against a solution of silver nitrate of known concentration. Chloride ions react with silver(I) ions to give the insoluble silver chloride:

$A{g}^{+}+C{l}^{-}⟶AgCl(K=5.88\times {10}^9$)

The yellow fluorescein is a common example used for the reaction i.e., -

$NaCl\left(aq\right)+AgN{O}_3\left(aq\right)\to AgCl\left(s\right)+NaN{O}_3\left(aq\right)$