Question

A solution contains the ions ag+ , pb2+ and ni2+. dilute solutions of nacl, na2so4 and na2s are available to separate the positive ions from each other. in order to effect separation, the solutions must be added in which order?

Answer 1

Use the sequence E (NaCl, Na2SO4, then Na2S). Silver is insoluble as a chloride, so it would be removed first, the others (Pb and Ni) are soluble as chlorides(Note; lead chloride is soluble as a hot solution but will ppt when cold), next, PbSO4 is insoluble but NiSO4 is soluble so use Na2SO4 to separate lead from nickel. Lastly, nickel sulfide is insoluble and can be separated and collected.

Hope I helped :)

Answer 2

Sequence will be:

NaCl

Na₂SO₄

Na₂S

Step-by-step explanation:

The silver ions get precipitated on addition of chloride ion as silver chloride.

So we will add NaCl in the first step.

The following reaction will occur.

`Ag^(+)+Cl^(-)--->AgCl(s)`

Lead and nickel are soluble in sodium chloride (lead chloride and nickel chloride).

`Pb^(+2)` will get precipitated as lead sulfate and nickel will remain soluble as nickel sulphate is soluble in water.

The reaction will be:

`Pb^(+2)+2SO_(4)^(-2)--->PbSO_(4)(s)`

Then nickel will be precipitated as sulfide.

The reaction will be:

`Ni^(+2)+2Cl^(-) ---->NiCl_(2)(s)`