Can you please help me develop a separation scheme with the pertinent equations

Question

Can you please help me develop a separation scheme with the pertinent equations for these 4 cations?

of Part 2: Designing and testing a separation seheme 2.1. Designing a separation scheme: Between Week 1 and Week 2 of lab, designa separation scheme for all 4 cations. Use the results of your preliminary tests and the reasoning illustrated in the introduction and the Pre-lab questions. Be sure to include equations for all the reactions which occur at each step in the scheme. Record the scheme in the data section of the lab notebook. The scheme MUST be submitted at the start of Week 2 laboratory period. It will be reviewed by the TA prior to the start of the lab period. Separation and Identification of Cations Lab Section12S Student Na s+ Cu fe Four Ions which may be present: A Ions that are present: uer ooservations that may not fit directly on the scheme

Explanation / Answer

If Ag+, Fe+3, CU2+ and AL3+ are present:

group I cations = Ag+

grooup II cations = Cu+2

group III cations = Fe+3 + Al+3

then...

for group I, Ag+, add HCl concentrated, so

Ag+ + Cl- --> AgCl(s) forms

precipitate the only solid, then only

Al+3, Cu+2 and Fe+3 are left

for group II ions,

in acidic solution, add H2S, so

Cu+2 + S-2 = CuS(s) will precipitate

then, filter and only

Al+3 + Fe+3 are left

add basic media, so OH forms for Al3+ and Fe3+

Fe+3 + 3NH4OH --> Fe(OH)3(s) + 3 NH4+

note htat aluiminium preicpoitates as OH-

2 Al(NO3)3 + 3 (NH4)2S + 6 H2O --> 2 Al(OH)3(s) + 6 NH4NO3 + 3 H2S

important:

Add extra NaOH, very concentrated ( 6M ) so

Al(OH)3(s) + OH-(aq) -- >Al(OH)4-(aq)

note that Fe(OH)3(s) remains as a solid

filter Fe(OH)3(s)

and now... we have

Al(OH)4- complex,

add some HCl, 1M, so

Al(OH)3(s) forms again, then filter, and we have all ions separated+ identificated

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