Could aqueous ammonia be used instead of hot water to separate lead ion from the

Question

1. Could aqueous ammonia be used instead of hot water to separate lead ion from the mixed chloride precipitate? Explain.
2. The test for Ag+ is to add HNO3 and see if a precipitate of AgCl forms. Where does the Cl- come from? Why does adding HNO3 make AgCl precipitate? Write an appropriate balanced reaction.
3. In the step where Ag+ and Hg2+ are being separated by addition of 6 M NH3, a student obtains a black precipitate and a clear, colorless supernatant for both the known and the unknown. The student concludes that both cations are present because the results are the same. Assess the student's conclusions for their accuracy, being sure to explain why the student is or is not correct for each cation.

Explanation / Answer

1)no,

PbCl2 does not react with aqueous ammonia
and so it would stay as PbCl2 (s) precipitated & mixed with the Hg(s) & Hg(NH2)Cl2 precipitates at the bottom of the testube

only Ag+ would be separated, as the AgCl dissociates into solution
forming the soluble [Ag(NH3)2]^+1 ion & Cl-1 ion

2) a typo in the text you have given. Silver chloride, AgCl, has low solubility in water. It can be formed by adding solutions of silver nitrate and sodium chloride together. Both of these solutions have very high water solubility, and are colorless solutions. No reduction or oxidation of the silver takes place; the reaction is a simple ligand exchange reaction.
The balanced chemical equation for the reaction would be:
AgNO3 + NaCl -> AgCl + NaNO3
All of the ions involved have a +1 or -1 charge.

3)The student is not correct. While the addition of ammonia immediately reveals the presence of Hg?

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