CHE251NBBL Experiment 3 - Cation Identification_Shahnavaz Ptel Lab Report

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Apr 3, 2024

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20 CHE25120231X3 SENECA COLLEGE OF APPLIED ARTS AND TECHNOLOGY Experiment 3 Cation Identification 1. This is an individual assignment. Please do not collaborate. 2. This report must be word-processed . 3. Marks for each section are provided Seneca Academic Policy on Cheating and Plagiarism (Sections 9.1 - 9.3): Cheating and plagiarism are offences that will not be tolerated by the college. Such offences occur when a student misrepresents his or her performance on any form of academic evaluation including, but not limited to, written assignments, lab experiments , group projects, test or examinations. The penalty for a first academic honesty offence is a grade of “0” on the work in which the offence occurred, and will result in a comment being placed on the transcript by the Academic Honesty Committee. The penalty for the second academic honesty offence is an “F” in the subject where the offence occurred, a second comment on the transcript and suspension from the College for a time period determined by the Academic Honesty Committee, normally for a minimum of three (3) semesters. When a student returns to the College, he/she will be placed on Academic Honesty Probation. Any further violation of the Academic Honesty policy will result in College initiated mandatory withdrawal for academic purposes. Name: Shahnavaz Patel Student ID#: 183137215 Partner(s): Smit Patel, Harsh Parmar Instructor: Nadia Kelton Due Date: 08-02-2023 Program: ETM Course: Fundamentals of Chemistry - Lab Course Code: CHE251-NBBL
Name: Shahnavaz Patel Date: 2023-02-08 3:21 AM Filename: Experiment 3 - Cation Identification_Lab Report.docx Page 2 of 6 CHE25120201X3 Purpose: /1 To determine the identity of the cations(group 1) present in an unknown solution based on their chemical properties. Results: /15 Fill in the blanks for the UNKNOWN sample with ID D3 . Use correct terminology e.g. chemical formulae, concentrations etc. Marks will be deducted for incorrect spelling. 1. When 4 drops of 6 M HCl was added to 10 drops de-ionized (DI) water and 10 drops group 1 cations, a white precipitate was observed. 2. The precipitate contained AgCl , PbCl 2 , and Hg 2 Cl 2 . 3. The supernatant contained cation from other groups . 4. The supernatant was eventually removed and 10 drops of DI was added to the precipitate. 5. The sample was then placed in a hot water bath. Once heated the supernatant was removed and split into two equal fractions. 6. In order to test for the presence of Pb +2 , one drop of 0.1 M K 2 CrO 4 was added to the first fraction and No PbCrO 4 precipitate was observed. Next, add one drop of 2 M H 2 SO 4 was added to the second fraction and no PbS0 4 precipitate was observed. Therefore, Unknown D3 , does not contains Pb +2 ions . 7. At this stage of the experiment, the remaining precipitate contains
Name: Shahnavaz Patel Date: 2023-02-08 3:21 AM Filename: Experiment 3 - Cation Identification_Lab Report.docx Page 3 of 6 CHE25120201X3 AgCl and Hg 2 Cl 2 . 8. In order to test for the presence of Hg +2 ions , 4 drops of 15 M NH 4 OH was added to the precipitate. Upon addition, no precipitate was observed. Therefore, Unknown D3 , does not contain Hg +2 ions . 9. At this stage of the experiment, the supernatant contains Ag + ions . 10. To test for Ag + ions , 16 M HNO 3 was added drop wise. The pH of the solution was tested using litmus paper . Once the solution turned acidic, the litmus changed colour from blue to red . 11. A white precipitate was observed. Therefore, Unknown D3 , contains Ag + ions . Discussion: /2 First, the experiment was carried out using a known solution where all three group 1 cation were detected then another run was carried out using an unknown stock solution with ID D3. The unknown solution with ID D3 contains Ag + ions, and no lead or mercury precipitates were observed. The precipitating agent used was hydrochloric acid. The HCl converts the group 1 cation to chloride compounds, and after further testing, no Pb + and Hg + ions were detected. However, Ag + ions present as AgCl was detected and confirmed by the following test. Ag + ions in AgCl are soluble in NH 4 OH and separate as white precipitates on acidifying the solution with 16 M HNO 3 . The white precipitate obtained is of AgCl. By adding ammonium hydroxide to the residue obtained in step 10, the silver chloride is selectively dissolved due to the formation of the soluble di-ammine silver (I) ion, which on acidification with nitric acid, gives precipitates of silver chloride. Overall reaction.
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