How would one go about separating the following substances. It's review for my test.
A solution contains Al3+, Ca2+, Fe3+
, and Ni2+
ions. Draw a flow chart that outlines the procedure
required to separate this mixture (use the back if you need more room)
There may be better, faster. and easier ways to do this but this is a fast write up, too. I can't do flow diagrams on this forum so take what I write and turn it into a flow diagram.
Add NaOH (but not a huge excess) to ppt Al, Fe and Ni. Ca is in the filtrate. To the ppt, add an excess of NaOH. That dissolves Al but not Fe and Ni. Add NH3 to dissolve the Ni(OH)2 and form the Ni(NH3)4^2+ but not the Fe(OH)2.
Done.
Thanks a lot Dr. Bob!
To separate the substances Al3+, Ca2+, Fe3+, and Ni2+ in the given solution, you can follow this flow chart:
1. Begin by adding sodium hydroxide (NaOH) solution to the solution.
- Al3+ will form a white precipitate of aluminum hydroxide (Al(OH)3).
- Ca2+ will also form a white precipitate of calcium hydroxide (Ca(OH)2).
- Fe3+ will form a reddish-brown precipitate of iron(III) hydroxide (Fe(OH)3).
- Ni2+ will not precipitate, remaining in the solution.
2. Filter the precipitate obtained in step 1 to separate it from the solution. The precipitate will contain Al(OH)3, Ca(OH)2, and Fe(OH)3.
3. Wash the precipitate with distilled water to remove any impurities or soluble ions.
4. Dissolve the precipitate in hydrochloric acid (HCl). This will dissolve Al(OH)3 and Ca(OH)2, forming Al3+ and Ca2+ ions in the solution, respectively.
5. Add ammonium carbonate (NH4)2CO3 to the acid solution obtained in step 4.
- Ca2+ will form a white precipitate of calcium carbonate (CaCO3).
- Al3+ will not precipitate and remains in solution.
6. Filter the precipitate obtained in step 5 to separate it from the solution. The precipitate will contain CaCO3.
7. Wash the precipitate with distilled water to remove any impurities or soluble ions.
8. Add ammonia (NH3) to the solution obtained in step 6.
- Fe(OH)3 will dissolve in the presence of excess ammonia to form a yellow solution of iron(III) hydroxide complex, [Fe(NH3)6]3+.
- Al3+ and Ca2+ will not react with ammonia and remain unaffected.
9. Filter the solution obtained in step 8 to separate it from any remaining precipitate or insoluble particles.
10. The filtered solution will now contain [Fe(NH3)6]3+ complex ions.
11. To separate Ni2+ from the rest, add dimethylglyoxime (DMG) solution to the filtered solution obtained in step 9.
- Ni2+ will form a red precipitate of nickel dimethylglyoxime.
- [Fe(NH3)6]3+, Al3+, and Ca2+ ions will not react with DMG and remain in solution.
12. Filter the precipitate obtained in step 11 to separate it from the solution. The precipitate will contain nickel dimethylglyoxime.
By following these steps in the flow chart, you can separate Al3+, Ca2+, Fe3+, and Ni2+ ions from the given solution. Remember to study and understand each step thoroughly for your upcoming test.