CHEM 105B Lab Report 9- Qualitative Analysis - Qualitative Analysis of Group I and Group III Cations Observations Part A Observations Known Unknown B-15

CHEM 105B Lab Report 9- Qualitative Analysis - Qualitative...

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Qualitative Analysis of Group I and Group III Cations Observations - Part A Observations Known -15 drops known + 1 dr 6M HNO 3 + 10 dr HCl >lime green with white precipitate -after centrifuge at 3000 RPM for 2 min > lime green clear solution with white precipitate at top Unknown B -15 drops unknown + 1 dr 6M HNO 3 + 10 dr HCl >yellow with white precipitate -after centrifuge at 3000 RPM for 2 min > yellow clear solution with white precipitate at top Part B Observations Known -added 1mL 1.0 M NaCH 3 COO to Part A precipitate >cloudy beige solution -added 1mL 1.0 M NaCH 3 COO again and centrifuged >slightly cloudy beige solution Unknown B -added 1mL 1.0 M NaCH 3 COO to Part A precipitate >clear beige solution -added 1mL 1.0 M NaCH 3 COO again and centrifuged >clear beige solution Part C Observations Known -added 2 dr yellow K 2 Cr 2 O 4 to supernatant from Part B >cloudy yellow solution -after centrifuging >clear yellow solution with precipitate at the top - indicates presence of Pb 2+ Unknown B -added 2 dr yellow K 2 Cr 2 O 4 to supernatant from Part B >clear yellow solution -after centrifuging >clear yellow solution, no precipitate Part D Observations
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Known -precipitate from Part B rinsed with 1mL DI water twice >clear with precipitate - Ag + present Unknown B -precipitate from Part B rinsed with 1mL DI water twice >clear with precipitate - Ag + present Part E Observations Known -15 dr 5M NaOH added to 1mL of Part A supernatant and centrifuged >clear lime green solution with blood colored precipitate with cotton candy consistency Unknown B -15 dr 5M NaOH added to 1mL of Part A supernatant and centrifuged >clear yellow solution with red orange colored precipitate with cotton candy consistency Part F Observations Known -precipitate from Part E dissolved with 16M HNO 3 , solution heated in the hot bath for five minutes >clear yellow solution -added 10dr 1M NH 4 Cl and 15dr 15M NH 3
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