Data Analysis
Table 1: Observations from Experiments
| Procedure | Observation | Proposed Equations | Identified Cations |
| 1 | no ammonia present |
Ag (aq) + OH (aq) -> AgOH (aq)
2Ni (aq) + 4OH (aq) -> 2Ni(OH)2 (aq)
2Pb (aq) + 4OH (aq) -> 2Pb(OH)2 (aq)
2Mn (aq) + 4OH (aq) -> 2Mn(OH)2 (aq)
2Fe (aq) + 6OH (aq) -> 2Fe(OH)3 (aq)
NH4 (aq) + OH (aq) -> (NH4)OH (aq)
2Al (aq) + 6OH (aq) -> 2AL(OH)3 (aq) |
Ag+, Pb2+, Ni2+, Mn2+, Fe3+, (NH4)+, Al3+ |
| 2 | no precipitate formed |
2Ni (aq) + 2HCl (aq) -> 2NiCl2 (aq) +2H2 (g)
2Mn (aq) + 2HCl (aq) -> 2MnCl2 (aq) + 2H2 (g)
2Fe (aq) + 6HCl (aq) -> 2FeCl3 (aq) + 3H2 (g)
3Al (aq) + 6HCl (aq) -> 2AlCl3 (aq) + 3H2 (g)
|
Ni2+, Mn2+, Fe3+, Al3+ |
| 6 | precipitate formed |
Ni (aq) + 2NaOH (aq) -> Ni(OH)2 (s) + 2Na (aq)
Mn (aq) + 2NaOH (aq) -> Mn(OH)2 (s) + 2Na (aq)
Fe (aq) + 3NaOH (aq) -> Fe(OH)3 (s) + 3Na (aq) |
Ni(OH)2 (s), Mn(OH)2 (s), Fe(OH)3 (s) |
| 7 | precipitate formed |
Mn (aq) + 2NaOH (aq) -> Mn(OH)2 (s) + 2Na (aq)
Fe (aq) + 3NaOH (aq) -> Fe(OH)3 (s) + 2Na (aq)
Ni (aq) + 6NH3 (aq) -> Ni(NH3)6 (s) |
Mn(OH)2 (s), Fe(OH)3 (s), Ni[(NH3)6]2+ |
| 8 | no precipitate formed | Fe(OH)3 (s) + 3H (aq) -> Fe (aq) +2H2O | Fe3+ |
| 9 | precipitate formed | 4Fe (aq) + 3[Fe(CN)6] (aq) -> Fe4[Fe(CN6)]3 (s) | Fe3+ |
| 10 | precipitate formed | Ni(NH3) (aq) + 2DMG -> Ni(DMG)2 (s) + 6NH3 (aq) | Ni2+ |
Conclusion
The purpose of this lab was to identify the cations in an unknown solution. To figure this out, a qualitative analysis procedure was performed. This is when the unknown solution is reacted with different reagents to determine what the unknown is. By knowing what a reaction would be if a specific ion is present, the uknown can be determined. The results found were that both Fe3+ ions and Ni2+ ions where found in the unknown solution based on the data obtained. There was only supposed to be one cation in the solution but somehow the unknown solution 2 had two different cations. Every lab group in the lab that had the unknown solution 2 all got the same results. Unknown solution 2 could have been contaminated before the lab procedure was started. This experiment could be made better in the future by making sure each solution used in the experiment is free from contaminations. Also making sure that while the experiment is being done, no contamination of anything is occuring. This could alter the results.