Question

In a group 1 analysis, a student obtained a precipitate containing both AgCl and PbCh. Which of the following reagents would enable separation of AgCl(s) from PbCl(s)? O Hys 0 Na2CO3 o KOH O NH3 O

Answer 1

The reagent that would enable the separation of AgCl from PbCl2 is NH3 (ammonia). (option D)

Why is this correct?

This approach involving ammonia (NH3) for the separation of silver chloride (AgCl) from lead chloride (PbCl2) is based on the differing solubilities of these compounds in ammonia solutions.

When AgCl is exposed to dilute ammonia, it forms a complex ion, [Ag(NH3)2]+, due to the formation of a soluble complex. The reaction occurs because ammonia molecules coordinate with the silver ions (Ag+) on the surface of AgCl, leading to the dissolution of AgCl as the soluble complex [Ag(NH3)2]+.

Answer 2

We can separate AgCl and PbCl₂ by adding hot water.

Step-by-step explanation:

In order to separate group one salts/ions is important to consider their solubility.

PbCl₂ is more soluble in water then AgCl and, when we increase water's temperature, PbCl₂ solubility icireases significantly. However, AgCl solubility does not change considerably.

Therefore, when we add hot water to the solution, the PbCl₂ will be dissolved and AgCl will remain as a precipitate.