Baeyer's Test for Unsaturation

Baeyer's Test

Experiment Overview

• Experiment No. 1: Test for Unsaturation - Baeyer’s Test
• Group 1: BS PSY 3202
• Members: Aday, Kianah Alessandra M.; Flores, Lorraine Allison D.; Mendoza, Maureen D.; Vasquez, Jewel Mae P.; Villaflores, Joydhel
• Date: February 3, 2025
• University: Batangas State University

Objectives

1. Understand Baeyer’s Test
2. Determine reagents that show positive or negative results based on color changes.
3. Differentiate between saturated and unsaturated samples.

Introduction

• Baeyer’s test detects unsaturation in organic compounds.
• Specifically identifies carbon-carbon double bonds (alkenes) or carbon-carbon triple bonds (alkynes).
• Uses Baeyer’s reagent: potassium permanganate ($KMnO_4$) solution (purple color).
• $KMnO_4$ is a strong oxidizing agent.
• Positive Result: Color change from pinkish-purple to brown indicates alkenes or alkynes (unsaturated compound).
• Negative Result: Purple color remains, indicating a saturated compound.
• Visual observation is crucial.
• Demonstrates oxidation reactions and the concept of unsaturation.

Materials and Methods

• Cleaning the workstation is a pre-lab requirement.

Results

Observations Table

Analysis and Discussion

• Test Tube A (Vegetable Oil):
  • Initially, $KMnO_4$ did not mix; no color change.
  • Mixed with oil, forming small particles.
  • Gradual color change to brown precipitate indicated unsaturation (positive result).
• Test Tube B (Cyclohexene):
  • Purple $KMnO_4$ color remained, indicating saturation (negative result).
  • Bubbles and a thin transparent liquid layer were observed.
  • Darker shade of purple compared to C and D.
• Test Tube C (Ethanol):
  • Purple $KMnO_4$ color remained, indicating saturation (negative result).
  • Lighter shade of purple compared to B.
  • Well-incorporated mixture; no precipitate.
• Test Tube D (Acetone):
  • Lightest shade of purple (faded $KMnO_4$).
  • Well-incorporated mixture; no precipitate.
  • Negative result, indicating saturation.
• Overall Conclusion: Vegetable oil is unsaturated, while cyclohexene, ethanol, and acetone are saturated.

Conclusion

• Baeyer’s test is effective for detecting unsaturated organic compounds.
• Vegetable oil showed unsaturation; cyclohexene, ethanol, and acetone did not.
• Positive result (color change) for vegetable oil; negative results (color remained) for the others.

Recommendations

1. Use a dropper with scale for improved accuracy in reagent addition.
2. Explore different reagents for testing unsaturation.
3. Standardize reaction times for consistent comparisons.

References

• https://chem.libretexts.org/Bookshelves/OrganicChemistry/OrganicChemistryLabTechniques(Nichols)/06%3AMiscellaneousTechniques/6.04%3AChemicalTests/6.4D%3AIndividualTests?fbclid=IwZXh0bgNhZW0CMTEAAR336-sVUsRV0mkbgazF5pWPlG-t6gAUW96SQ-2oKkkxS7YZRe3jCbEvUoUaem_NVTzq5CC0fweCaV2TDYKfQ
• https://theory.labster.com/baeyers-test/
• https://unacademy.com/content/question-answer/chemistry/what-is-baeyers-reagent/
• https://byjus.com/chemistry/tests-for-unsaturation/