Question

: Which solution makes the white precipitate of silver chloride soluble in it?

Answer 1

Hint :Precipitate is the insoluble ionic substance that is left behind in the reaction mixture due to the combination of anions and cations along with the products. To make a precipitate soluble it has to form a salt with the solvent. If the precipitate salt is formed, the precipitate is soluble.

Complete Step By Step Answer:
The reaction between Potassium chloride (KCl) and silver nitrate ( $ AgN{{O}_{3}} $ ) results in the formation of Silver nitrate (AgCl) as the precipitate. The precipitation reaction is given as below:
 $ AgN{{O}_{3}}_{\left( aq \right)}\text{ }+\text{ }KC{{l}_{\left( aq \right)}}\text{ }\to \text{ }AgC{{l}_{\left( precipitate \right)}}\text{ }+\text{ }KN{{O}_{3}}_{\left( aq \right)} $
The white solid precipitate of Silver chloride is soluble in:
1. Ammonia solution-
AgCl reacts with NH3 to form $ {{[Ag{{(N{{H}_{3}})}_{2}}]}^{+}} $ a soluble salt. The reaction is as follows:
 $ AgCl + 2NH_3 \to {[Ag(NH_3)_2]^+} + Cl^- $
2. Sodium thiosulphate ( $ {{S}_{2}}{{O}_{2}} $ ) solution-
AgCl reacts with $ {{S}_{2}}{{O}_{2}} $ to give $ {{[Ag{{({{S}_{2}}{{O}_{3}})}_{2}}]}_{3}}^{-} $ as a salt. The reaction is shown below:
 $ AgCl\text{ + 2(}{{S}_{2}}{{O}_{2}}{{)}^{-3}}\to \text{ }{{[Ag{{({{S}_{2}}{{O}_{3}})}_{2}}]}_{3}}^{-}\text{ + C}{{\text{l}}^{-}} $
3. KCN solution-
AgCl reacts with CN- or KCN to form $ {{[Ag{{(CN)}_{2}}]}^{-}} $ salt. The reaction is as follows:
 $ AgCl\text{ + 2C}{{\text{N}}^{-}}\to \text{ }{{[Ag{{(CN)}_{2}}]}^{-}}\text{ + C}{{\text{l}}^{-}} $
4. Concentrated KCl solution-
AgCl forms $ {{[AgC{{l}_{2}}]}^{-}} $ a soluble complex when it reacts with KCl. The equation is as follows:
 $ AgCl\text{ + C}{{\text{l}}^{-}}\to {{[AgC{{l}_{2}}]}^{-}} $
5. Ammonium hydroxide-
Ammonia dissolved in water forms Ammonium Hydroxide. AgCl reacts with NH4OH to give $ \left[ Ag{{\left( N{{H}_{3}} \right)}_{2}} \right]Cl $ i.e. Diamine silver chloride which is soluble in water.
Thus, AgCl is soluble in the above-given solutions.

Note :
AgCl is a precipitate that becomes soluble when it forms a salt with the compound. It is not directly soluble in water. But if the compound forms a solution in water then AgCl readily dissolves in it. The precipitation reactions help to determine the occurrence of various ions present in a certain solution.