Unknown Cation Test Pre labIntroductionThe overall purpose of this lab is to develop a scheme to separate and identify three unknown cations from a solution, and then perform this scheme to perfection. This will be done by adding different solutions to the main cation solution and carefully watching to see what precipitates. The techniques that will be used in this lab include centrifuging and decanting. A centrifuge rotates very quickly to separate substances with different densities1. Decanting is defined as pouring gently as to not disturb the sediment. This can also be done by a pipet to ensure none of the precipitate or sediment is disturbed1. Making schemes is also a major technique in this lab. The process of making ascheme is always used in science for all labs. This includes figuring out what the end result wanted is and then developing ideas on how to achieve this end result.In this lab there will be a solution with three unknown cations. Of these three there are five possibilities, which include Ag+, Pb2+, Cu2+, Ni2+, and Fe3+. In the scheme that is mentioned later in the procedure, there are five possible reactions that will occur inthis lab. They are as follows:Ag+ (aq) + Cl- (aq)  AgCl (s)Pb2+ (aq) + Cl- (aq)  PbCl2 (s)Cu2+ (aq)+ S2- (aq) CuS (s)Fe3+ (aq)+ OH- (aq)  Fe(OH)3 (s)The following will be a confirmation test as shown in the scheme, because Nickel will not precipitate with the solutions present. Also the NH3 will be basic.Ni2+ (aq) + DMG (s) + NH3 (aq)  Ni(DMG)2This solution created should be strawberry red color. These are the main reactions that take could take place in this lab. Not all of them will due to the fact that there will only be three of the five listed ions present.The separation and identification of unknown cations is very important in the world today. Many water supplies are contaminated with these unknown cations and without separation schemes and techniques these would be consumed by humans and animals alike. A Geochemical process in Denmark was used to separate unwanted cationsfrom the water from freshwater and saltwater. This process helps many different living (1)(2)(3)(4)(5)2things and is very important3. A method was designed in China to separate cations from waste to help cleanse the solutions to make them easier to dispose of4. Also the use of cation treatment as seen in china is seen in many other ways to treat wastewater in many other instances. Also there are cases that also treat acid mine drainage by developimg a scheme and carrying it out to rid of unwanted cations5. In all of these instances a group ofscientists developed a scheme to separate cations, and then carried out that idea to determine which cations were present and the way to rid of them from the solution. This is exactly what will be done in this lab.Table of ReagentsReagent Molar Mass(g/mol)Density(g/mL)Melting Point (°C)Boling point (°C)Hazards3M HCl 36.46 1.048 -18 103 -Harmful if Swallowed.-Severe irritation to skin,eyes respiratory tractH2O 18.02 1 0 100 NoneK2Cr2O7294.2 2.68 398 500 -Corrosive-Harmful if Swallowed-Can Cause CancerH2S/H+34.08 1.363 -82 -60 -Explosive in gas form-Harmful if swallowedNH4Cl 53. 1.527 338 520 -Harmful if Swallowed-skin and respiratory irritantNH4OH 35.04 .91 24.7 -91.5 -Harmful if swallowed-skin and respiratory irritantDMG 103.12 1.069 180 175 -can be hazardous if over inhaledNH317.031 .73 -77.73 -33.34 -Harmful if swallowed-skin eye and respiratoryirritantThe table of reagents includes the information about the reagents that will be used in this expirament2.3ProcedureMany of the techniques and much of the procedure can be found in the lab manual, but in this instance much of the procedure is developed by the student. Also, the procedure will determine which cations are present in the solution given. This will cause much of the procedure to be hypothetical and some of it may not be used in the actual lab. 1. The first step is to obtain the necessary equipment to perform this lab. 2. Obtain the solution and place the unknown cation solution into a test tube andplace the test tube in a test tube rack3. Add a few drops of HCl to the solution. If there is a precipitate go to number 4. If not go to number 5.4. A white precipitate formed therefore there is either Pb2+ , Ag+a. First, Centrifuge the precipitate then decant. Place the decanted solution into another test tube.b. Heat DI water to a boilc. Add DI water to the decanted precipitate, if it dissolves, the precipitate is PbCl2. If not, the precipitate is AgCl, If some dissolves and some does not,they are both in the solution. 4d. Decant the solution from the precipitate and perform a confirmation test for Pb2+ by adding K2Cr2O7 if it was determined that Pb2+ was in the solution5. Add Acidic H2S to the test tube. If nothing has precipitated before this addition at this moment the three cations in this solution are Cu2+, Ni2+, and Fe3+. a. If a black precipitate forms CuS has been formed.6. After a precipitate forms, centrifuge and decant the solution. Place the decanted solution into a new test tube7. Now add NH4OH to buffer the decanted solution, then add NH4Cl. If there is aprecipitate Fe(OH)3 has formed. Centrifuge and decant the solution to a new test tube.8. Now perform a confirmation test for Ni2+. This includes adding DMG and basic ammonia to the decanted solution. If a red precipitate forms there is Ni2+in the solution. 9. At this point, all of the cations should be known in the solution. References1. Dictionary.com. Dictionary.com, n.d. Web. 2013.2. http://www.atmos.umd.edu/, Material Safety Data Sheet. N.d. Web. 20133. Anderson M.S., Nyvang, V., Jackobsen, R., Potsma D.: Geochemical processes and solute transport at the seawater/freshwater interface of a sandy aquifer. Technical university of Denmark. 69.16 pp3979-39944. Ma, J.-Y., Hong, X.-P., Ma, Z.-Y., Yan, J.-H., Ni, M.-J., Cen, K.-f. Determination of inorganic cations in high concentration organic liquid wastes by ion chromatography. (2007) Jiliang Xuebao/Acta Metrologica Sinica, 28(2)5. Buzzi, D.C., Veigas, L.S., Silvas, F.P.C., Rodrigues, M.A.S., Espinosa, D.C.R., Schneider, I.A.H., Bernardes, A.M., Tenorio, J.A.S.; 140th annual meeting and exhibition San diego CA, Volume 1, 2011, pp 277-2846. University of Illinois at Urbana-Champaign. An Introduction to Chemical Systems in the laboratory: Chem 203/205. 2013-2014 ed. Hayden-Mcneil: Plymouth, MI, 20135Questions to Consider1. HCl reacts very