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Park 1What is in my sample? “Let’s find the cations”Chemistry 106- Lab 4Introduction: In this lab, we had to identify cations in a mixture through qualitative analysis. Qualitative analysis is when species in a mixture are separated and identified. This helps to verify the presence of cations in groups 1, 2, and 3. We found out what cation was present after adding chemicals to the solution and watching what reaction occurred afterwards. We then separated the solid and liquid by centrifuging and then decantationing. Centrifugation will separate the precipitate and liquid solution due to gravity. Then decantation will be performed byputting the liquid into another tube to separate the mixture of solid and liquid. Materials: ●Test tube rack~ Holds the multiple test tubes being used in the lab.●Small test tube~ Glassware used to hold solutions.●Cation solution and unknown solution~ Solutions used during lab.●KI~ Potassium iodide used in lab.●6M NH3~ 6M ammonia used in lab. ●0.1M NH3~ 0.1M ammonia used in lab.●6M HNO3~ 6M nitric acid used in lab.●6M HCl~ 6M hydrochloric acid used in lab.●1M solution thioacetamide~ Used in lab.●3% H2O2~ Hydrogen peroxide used in lab.●Hot water~ Used to mix with precipitates and to also heat up test tubes inside of beakers.●Centrifuge~ Machine with a rapidly rotating container that separates liquids from solids.●Graduated cylinder~ Used to measure the volume of liquids. ●Pipette~ Used to transfer small amounts of liquids.Observations and Experimental: Part A:Cation Mixtures:Ag, Pb², Hg², Cu², Bi³, Fe³⁺⁺₂ ⁺⁺⁺⁺Step 1:Add 4 drops of HCL.1.Ag⁺(aq) + Cl⁻(aq) → AgCl(s)
Park 22.Pb²⁺(aq) + 2Cl⁻(aq) → PbCl₂(s)3.Hg₂²⁺ + 2Cl⁻(aq) → Hg₂Cl₂(s)4.Cu²⁺(aq) + Cl⁻(aq) → No reaction5.Bi³⁺(aq) + Cl⁻(aq) → No reaction6.Fe³⁺(aq) + Cl⁻(aq) → No reaction4 drops of 6M HCl was added to the solution and the cation solution turn a cloudy yellow-green color. We then centrifuged the solution and the solid(precipitate) turned out to be white while the liquid(supernatant) turned out to be green.Step 2:Add 2 mL of hot water.PbCl₂(s) → Pb²⁺(aq) + 2Cl⁻(aq) ← supernatantAgCl(s) → No reaction ← precipitateHg₂Cl₂(s) → No reaction ← precipitateAfter adding the 2 mL of hot water, the solution turned milky. After centrifuging, the solution separated into clear supernatant and white solid at the bottom.