Qualitative Analysis of Anions Essay

The objective of this experiment was to social function qualitative analysis to determine the chemic characteristics of four known anions by systemic defendatory rendering. The chemic characteristics observed were to be employmentd to constitute an unknown smack. Sulphuric pane of glass was to be added to a carbonate resolve and an glistering response would confirm the mien of carbonate anions. Another sampling of carbonate base was to be reacted with hydrochloric venereal infectionic and the fluffeous product was to be reacted with a suspended drop of atomic number 56 carbonate. The armorial bearing of cloud in the droplet would also confirm the nominal head of carbonate anions. Silver treat was to be added to chloride theme and the composition of a bloodless descend, bills chloride, would confirm the movement of chloride anions. Ammonium hydroxide would be added to dissolve part of the accrue.The responseant supernatant root word was to be decanted and re-acidified with nitric acid to re socio-economic class the devolve and definitively confirm the mien of the chloride anion. Silver nitrate was to be added to iodide final result and the brass of a color precipitate, silver grey iodide, would confirm the figurehead of iodide anions. Another model of iodide radical was to be reacted with drops of acetic acid until sufficiently vitriolic. Potassium nitrate was to be added to the solution causing a annotate counterchange. Methylene chloride was to be added to this prove and shaken to confirm the presence of iodide anions by forming two separate and differently coloured forges. A atomic number 56 chloride-calcium chloride premix was to be added to sulfate solution and heated to 90oC. The take in was to stand for a period of time to relinquish the formation of a unclouded precipitate, barium sulfate, coercive the presence of the sulphate anion. The concomitant of hydrochloric acid and subsequent estrus were to have no motion on the presence, come along verificatory the presence of sulphate anions.MATERIALS AND METHODSEQUIPMENTCHEMICALSTest pipagescarbonate Solution,Test thermionic provide rackConcentrated Sulphuric acid, H2SO4Eye dropper6M Hydrochloric acid, HCLGraduated pipetteBarium hydroxide solution Ba(OH)2Pipette medulla oblongataChloride solution, Cl-Pasteur pipetteIodide solution, I-Beaker0.1M Silver nitrate, AgNO3ThermometerConcentrated Ammonium hydroxide, NH4OH6M Nitric acid, HNO36M Acetic acid. HC2H3O2Potassium nitrate, KNO2Methylene chloride solution, CH2Cl2Sulphate solution,Barium chloride-Calcium chloride mixture, BaCl2-CaCl2 unfathomed archetype 7SAFETYCarbonate solution is uncertain in fount of come up dawn (sensitizer, irritant), of warmheartedness contact (irritant), ingestion (lung irritant), and ingestion. It should be kept in a cool, well-ventilated area. In case of spill, use set aside tools to put the spilled lusty in a convenient raving mad dispos ition container and even off the symmetry with a load solution of acetic acid. Hydrochloric acid is genuinely(prenominal) fantastic in case of trim contact (sensitizer, corrosive, irritant, permeator), substance contact (corrosive, irritant), of breathing in (lung sensitizer, respiratory tract irritant), and ingestion (toxic). It should be kept in a dry container, kept away from oxidizing agents, organic materials, metals, alkalis, and moisture. In case of spill, reduce with urine and disinfect with an sloughy dry material. Resi cod should be neutralized with dilute sodium carbonate. Chloride solution is untamed in case of flake off contact (irritant, permeator), of midsection contact (irritant), ingestion, and inhalation (irritant).In case of spill, dilute with water and mop with an inert dry material and spread water on the contaminate surface. Iodide solution is lightly hazardous in case of skin contact (irritant), of heart and soul contact (irritant), of ingesti on, and inhalation. In case of spill, use appropriate tools to put the spilled solid in a convenient waste disposal container. And spread water on the contaminated surface. Silver nitrate is very hazardous in case of skin contact (corrosive, permeator), of eye contact (irritant), of inhalation, and ingestion.. Silver nitrate kept away from heat, sources of ignition, and combustible material. In case of spill, use appropriate tools to put the spilled solid in a convenient waste disposal container. Ammonium hydroxide is very hazardous in case of skin contact (toxic, corrosive, irritant, permeator), eye contact (irritant), inhalation (toxic to upper respiratory tract), and ingestion (toxic). Water should never be added to ammonium ion hydroxide and it should be kept away from incompatibles such as metals, acids. In case of spill, dilute with water and mop with inert dry material. sabotage residue with dilute acetic acid. Nitric acid is very hazardous incase of skin contact (corrosive, irritant, permeator), of eye contact (irritant, corrosive), and ingestion. It is jolly hazardous in case of inhalation (lung sensitizer, respiratory tract and mucus membrane irritant). Nitric acid is explosive in the presence of simplification materials, of organic materials, of metals, of alkalis. In case of spill, dilute with water, mop with an inert dry, and neutralize the residue with a dilute solution of sodium carbonate. Acetic acid is very hazardous in case of skin contact (irritant), of eye contact (irritant), of ingestion, of inhalation. It is hazardous in case of skin contact (corrosive, permeator), of eye contact (corrosive). It should be kept away from sources of heat, ignition, and oxidizing material. In case of spill, disregard with water, mop with an inert dry, and neutralize the residue with a dilute solution of sodium carbonate.Potassium nitrite is extremely hazardous in case of skin contact (corrosive, irritant), of eye contact (irritant), of ingestion, and inha lation. In case of spill, use appropriate tools to put the spilled solid in a convenient waste disposal container. Potassium nitrite should be kept dry, away from sources of ignition, heat, and combustible materials. Methylene chloride is very hazardous in case of eye contact (irritant), of ingestion, of inhalation, and skin contact (irritant, permeator). In case of spill dilute with water and mop with an inert dry material. Sulphate solution is hazardous in case of eye contact (irritant), skin contact (irritant), and ingestion. In case of skin contact, weaken with soap and water, and c tout ensemble everyplace area with an emollient. In case of spill, Dilute with water, mop with an inert dry material spread water on the contaminated surface. (ScienceLab, 2005)PROCEDUREPlease refer to Lab 3 Qualitative compendium Part 2- Anions chemistry Laboratory Manual 2013-2014, Durham College, pages 11-12 for full inclination of an orbit of Materials and Methods.OBSERVATIONS circuit board 1a scrutiny for the presence of Carbonate, CO32- anions2 drops tough H2SO4 added, Test tube shakenAdditional ObservationsCarbonate Solution, 3mLeffervescence seen as colourless splosh rises from bottom of screen out tube screen out tubefeels much warmer, upon wafting the gas has a mildly unpleasant, acrid smell The presence of an effervescent chemical reaction indicated that the sample had carbonate anions present.Table 1b exam for presence of Carbon Dioxide, carbon dioxide to confirm the presence of CO32- anions2 drops 6M HCl1 drop BaOH suspended over rise tubeCarbonate Solution, 3mL atrophied amount of effervescence noteabout 5 seconds after being suspended over test tube, the base of the droplet clouded with white precipitate The appurtenance of HCl to the sample resulted in some rising gas bubbles, indicated that a gas was being organize. The clouding of the barium hydroxide droplet indicated it was reacting with carbon dioxide escaping the tube and thus confirmed th e presence of carbonate anions in the sample. Table 2 scrutiny and confirming for the presence of Chloride, Cl- anions5 drops 0.1M AgNO3 addedNH4OH is added drop-wiseSupernatant solution is decanted,6M HNO3 is addedChloride Solution, 5mL soggy white precipitate organiseprecipitate partially dissolved upon addition, distinct micturate supernatant organise above remaining precipitate soggy white precipitate reformed, small white granulations settled at bottom of test tube 6 drops of ammonium hydroxide, NH4OH, were added to the sample 6 drops of the nitric, HNO3, were added to acidify the sample The formation of a dingy white precipitate in the presence of silver nitrate indicated that the sample had chloride anions present. The subsequent addition of ammonium and re-acidification of the sample resulted in the rehabilitation of a cloudy whit precipitate, thus confirming the presence of chloride anions. Table 3a Testing for the presence of Iodide, I- anions5 drops 0.1M AgNo3 add edIodide Solution, 5mLcloudy pale yellow precipitate formedThe presence of a cloudy yellow precipitate with silver nitrate indicates presence of iodide anion. Table 3b Testing and confirming the presence of Iodide, I- anionsAcetic acid is added drop-wise2 drops KNO2 added15 drops Methylene chloride added, test tube shakenIodide Solution, 5mLBlue Litmus Paper confirmed the solution was acidic by turning red solution turned a mustard-brown colour2 distinct seams formed in the test tube. The bottom layer was reddish magenta, and the tweet layer was a burnt-orange colour 2 drops of acetic acid, HC2H3O2, were added to acidify sample Upon confirming the sample was indeed acidic, it reacted with the chiliad nitrate to change to a mustard-brown colour. The addition of the methylene group chloride formed 2 intelligibly coloured layers, thus confirming that the solution had iodide anions present.Table 4 Testing and confirming the presence of Sulphate SO42- anions0.5mL of BaCl2-CaCl2 mixtu re addedTest tube heated, stood for 10 minutes5 drops 6M HCl, test tube heatedSulphate Solution, 3mLvery faint wisps of cloudy white precipitate appearednoticeable cloudy white precipitate distributed throughout solution addition of HCl made test tube feel warmafter heating test tube precipitate remained dispersed in solution In each instance of heating, the test tube was placed in a boiling water bathtub at 90oC The final heating of the test tube was for approximately 5minutes at 90oC The reaction of the sulphate solution with the barium chloride-calciumchloride solution, when heated, resulted in the appearance of a fine white precipitate, indicating the sample had sulphate anions present. The subsequent addition of HCl and reheating resulting in the solution remaining relatively the same pull ahead confirmed that sulphate anions were present. Table 5a Testing for abstruse consume 7 for the presence of Carbonate, CO32- anions2 drops concentrated H2SO4 added, Test tube shakenAdd itional Observations unvalued consume 7, 3mLno visible effervescenceno noticeable change to test tubes temperatureThe lack of effervescence and heat make growd by the sample indicated the absence of carbonate anions in the sample. Table 5b Testing Unknown prototype for presence of Carbon Dioxide, CO2 to confirm the presence of CO32- anions2 drops 6M HCl1 drop BaOH suspended over test tubeUnknown Sample 7, 3mLno noticeable effervescencesuspended droplet remained clear, despite being held over test tube for 15 seconds The sample did not react with the hydrochloric acid to produce a gas that reacted with the barium hydroxide, thus the suspended droplet remained clear. The results further confirmed the absence of carbonate anions. Table 6 Testing and confirming Unknown Sample for the presence of Chloride, Cl- anions5 drops 0.1M AgNO3 addedNH4OH is added drop-wiseSupernatant solution is decanted,6M HNO3 is addedUnknown Sample 7, 5mLpale yellow precipitate formedno change to solutionno change to solution6 drops of ammonium hydroxide, NH4OH, were added to the sample Nitric acid, HNO3, was unable to be added to the precipitate as no clear supernatant was formed The lack of formation of a cloudy white precipitate in the presence of silver nitrate indicated that the sample did not have chloride anions present. The subsequent addition of ammonium and re-acidification of the sample were rendered purposeless. Table 7a Testing Unknown Sample for the presence of Iodide, I- anions5 drops 0.1M AgNo3 addedUnknown Sample 7, 5mLcloudy pale yellow precipitate formedThe presence of a cloudy yellow precipitate with silver nitrate indicates presence of iodide anion. Table 7b Testing and confirming Unknown Sample for the presence of Iodide, I- anionsAcetic acid is added drop-wise2 drops KNO2 added15 drops Methylene chloride added, test tube shakenUnknown Sample, 5mLBlue Litmus Paper confirmed the solution was acidic by turning red solution turned a mustard-orange colour2 distinct l ayers formed in the test tube. The bottom layer was reddish-purple, and the top layer was an orange-brown 2 drops of acetic acid, HC2H3O2, were added to acidify sample Upon confirming the sample was indeed acidic, it reacted with the potassium nitrate to change to a mustard-orange colour. The addition of the methylene chloride formed 2 distinctly coloured layers, thus confirming that the solution had iodide anions present. Table 8 Testing and confirming Unknown Sample for the presence of Sulphate SO42- anions0.5mL of BaCl2-CaCl2 mixture addedTest tube heated, stood for 10 minutes5 drops 6M HCl, test tube heatedUnknown Sample, 3mLno precipitate formedno noticeable precipitate formedno change to solutionIn each instance of heating, the test tube was placed in a boiling water bath at 90oC The final heating of the test tube was for approximately 5minutes at 90oC The lack of precipitate formation in the test indicated that the sample was absent of sulphate anions. This result was further confirmed by the subsequent addition of hydrochloric acid and reheating failing to produce a precipitate.DISCUSSIONA strong acid such as H2SO4, sulphuric acid, combined with carbonate produces an effervescent reaction due to the formation of carbon dioxide. The heat felt from the test tube was a result of the exothermic reaction that the carbonate solution underwent in the presence of a strong acid. Sulfuric acid is a strong acid, but yet for the first H, so it dissociates into H+ ion and the bisulfate ion, HSO4-. HSO4- is a weak acid and does not dissociate to a great extent, but it also reacts with carbonate (Dartmouth College, 2003). The presence of sulphur may have accounted for the mildly unpleasant scent wafted during the experiment. As indicated by the results of Table 1b, the formation of CO2 acted as a positive indicator for the presence of CO32- in a solution, as verbalized by 2H+(aq) + CO32-(aq) H2O(l) + CO2(g).The exposure of the produced gas, carbon dioxide, to bari um hydroxide resulted in the a cloudy white precipitate due to the formation of barium carbonate as verbalized by H2O (l) + CO2 (aq) + Ba2+(aq) BaCO2 (s) + 2 H+(aq). The addition of 01M AgNO3, silver nitrate, to the chloride solution resulted in the formation of a white precipitate due to the formation of silver chloride as expressed by AgNO3 (aq) + Cl-(aq) AgCl(s) + NO3 (g). It is kindle to note that chlorides are mainly soluble, with the exception of lead(II) and silver chloride. When concentrated NH4OH was added to the silver chloride precipitate dissolved due to the formation of an ammine complex, Ag(NH3)2+. Silver nitrate is generally acidified with dilute nitric acid to prevent the precipitation of other non-halide silver salts (Brown, 2012).Nitric acid acidified the solution due to the addition of H+ ions to the solution, resulting in re-precipitation, thus definitively indicating the presence of chloride anions. This is expressed as AgCl(s) +2NH3(aq) Ag(NH3)2+(aq) + Cl -(aq) Ag(NH3)2+(aq) + Cl-(aq) + 2H+(aq) AgCl(s) + 2NH4+(aq) The addition of 0.1M AgNO3 to the iodide solution resulted in the formation of a cloudy yellow precipitate as expressed by AgNO3(aq) + I- AgI(s), which as a precipitate is insoluble in concentrated ammonia. The addition of 6M acetic acid, HC2H3O2, acidified the solution, as confirmed by the litmus test. The impudently acidic solution reacted with potassium nitrite, KNO2, reducing the nitrite to nitrogen dioxide as expressed by I-(aq) + KNO2 KI(aq) + NO2(g). The liberation of iodine in the reaction resulted in a brownish change in colouration of the solution (SUNY Chemisty, 2005). The failure of the sample to turn a reddish-brown may have been a source of error due to a failure to sufficiently rinse the cleaned test tube with DI water.Methylene chloride, CH2Cl2, which is a non-polar organic compound was added to the solution reacted with the iodide in the solution to form a violet coloured layer of denser solution, which settled at the bottom of the test tube. An alternative means of testing for the presence of iodide anions would have been to use starch, which forma a characteristic blue-black complex. The addition of the barium chloride-calcium chloride mixture, BaCl2-CaCl2, to the sulfate solution resulted in the formation of an insoluble white sulphate, barium sulphate as expressed by Ba2+(aq) + SO42-(aq) BaSO4(s). Other insoluble barium salts contain anions of weak acids (CO32-, SO32-and PO43-). Precipitation of these anions is generally prevented by acidifying the solution (Yoder, 2014). The products of the reaction were made more prominent by the catalyzing the reaction with heat, resulting in a more noticeably fine white precipitate distributed throughout the solution.The addition of 6M HCl, hydrochloric acid, served to acidify the solution, further illustrating the insolubility of the barium sulfate precipitate, thereby confirming the presence of sulphate anions. The unknown sample was p laced through all confirmatory tests. It failed to react with Sulphuric acid and hydrochloric acid to produce an effervescent reaction, indicating it was carbonate absent. Unknown Sample 7 did not react with the BaCl2-CaCl2 mixture to form a precipitate regardless of heat, indicating the absence of sulphate anions. Unknown Sample 7 formed a pale cloudy yellow precipitate upon the addition of silver nitrate, immediately indicating the presence of iodide anions, disqualifying the command to testfurther for chloride. The addition of acetic acid to Unknown Sample 7 provide a sufficient acidic environment for the potassium nitrate to release iodine, thus the solution appeared as a shabbiness mustard orange. The methylene chloride confirmed the presence of iodide anion when a distinct reddish-purple layer settled at the bottom of another distinctly coloured layer of solution.CONCLUSIONBased on the results of the experiment, Unknown Sample 7 demo the formation of a precipitate in the pr esence silver nitrate, a change in colouration when mixed with potassium nitrate, and the formation of 2 distinctly coloured layers when methylene chloride was added to the solution and shaken. In accordance with the chemical properties exhibited by the 4 known anions during the qualitative testing, it can be think the Unknown Sample 4 clearly demonstrated the characteristic chemical responses of a solution with I- ions present.QUESTIONS1. An ion is an atom that has lost or gained an electron to form a charged particle.2. An anion is a negatively charged particle due to the atom gaining one or more electrons. A cation is a positively charged particle due to the atom losing one or more electrons.3. H2SO4(aq) + Na2CO3(aq) Na2SO4(aq) + H2O(l) + CO2(g)4a. Aluminum ion pigeonholing IIIA, Al3+4b. Sulphur ion Group VIA, S2-4c. Iodide ion Group VIIA, I-4d. Oxygen ion Group VIA, O2-4e. Chloride ion Group VIIA, Cl-REFERENCESBirk, J. P. (2001, December 4). General chemical science With Qua litative synopsis. Retrieved from Arizona disk operating system University http//www.public.asu.edu/jpbirk/qual/qual.html Brown, W. (2012). Chemical Tests. Retrieved from Doc Browns Chemistry http//www.docbrown.info/page13/ChemicalTests/ChemicalTestsa.htm DartmouthCollege. (2003, May). ChemLab Chapter 5. Retrieved from Qualitative digest of Cations http//www.dartmouth.edu/chemlab/chem3-5/qual_an/overview/procedure.html ScienceLab. (2005, October 10). Material Safety Data Sheet (MSDS) List. Retrieved from Science Lab http//www.sciencelab.com/msdsList.php SUNY Chemisty. (2005, December). Anion Analysis. Retrieved from Chemistry 112 http//employees.oneonta.edu/kotzjc/LAB/Anion.pdf Tro, N. J. (2011). Essential Introductory Chemistry (4th ed.). Toronto Prentice Hall. White, R. (2013-2014). Qualitative Analysis Part 2- Anions. Chemistry 1 Laboratory Manual, 7-9. Yoder, C. (2014, November). Qualitative Analysis of CAans and Anions. Retrieved from fit Chemist http//www.wiredchemist.com/ chemistry/instructional/laboratory-tutorials/qualitative-analysis