Explain the following statement. When aqueous ammonia is added to solution containing Pb2+ ions, a white precipitate is formed.
Maybe lea nitrate ?
lead nitrate is soluble. The white ppt formed with NH3 is Pb(OH)2.
NH3 + H2O ==> NH4^+ + OH^-
Pb^2+ + 2OH^- ==> Pb(OH)2
1. Aqueous ammonia is a solution of ammonia dissolved in water. This solution contains NH3 molecules and OH- ions.
2. Pb2+ ions refer to lead ions with a positive 2 charge. These ions can be present in a solution.
3. When the aqueous ammonia solution is added to a solution containing Pb2+ ions, a chemical reaction occurs.
4. The ammonia molecules in the solution will react with the Pb2+ ions. The reaction can be represented by the following equation:
Pb2+ + 2NH3 → Pb(NH3)2
5. The reaction results in the formation of a new compound called lead(II) ammine, which is represented as Pb(NH3)2.
6. This lead(II) ammine compound is not soluble in water and forms a solid, known as a precipitate.
7. The precipitate appears as a white solid, indicating that it reflects and scatters light in such a way that it appears white to the human eye.
In summary, when aqueous ammonia is added to a solution containing Pb2+ ions, a chemical reaction occurs, resulting in the formation of a white precipitate, which is lead(II) ammine compound (Pb(NH3)2).
The statement is explaining the reaction between aqueous ammonia and a solution containing Pb2+ ions, resulting in the formation of a white precipitate. A precipitate is a solid that forms when two solutions are mixed together and react chemically.
To understand why this reaction occurs and how the white precipitate is formed, we need to consider the chemistry behind it. In this case, aqueous ammonia (NH3 dissolved in water) reacts with lead(II) ions (Pb2+) to produce a compound called lead(II) hydroxide, which is a white solid. The reaction can be represented by the following equation:
Pb2+(aq) + 2NH3(aq) -> Pb(OH)2(s) + 2NH4+(aq)
In this equation, Pb2+ from the solution reacts with NH3 from the aqueous ammonia, forming Pb(OH)2, which is insoluble in water and therefore precipitates out as a solid. Additionally, NH4+ ions are formed as a result of the reaction.
To observe this reaction, one needs to add aqueous ammonia, usually in a controlled manner, to a solution containing Pb2+ ions. As more ammonia is added, the lead(II) hydroxide precipitate gradually forms, appearing as a white solid in the solution.
In summary, the statement explains that when aqueous ammonia is added to a solution with Pb2+ ions, a chemical reaction occurs, leading to the formation of a white precipitate called lead(II) hydroxide.