Reactivity of cyclohexane, cyclohexene and toluene

Summary

In this experimental video, the presenter conducts a chemistry investigation involving cyclohexane, toluene, and hexane in a fume hood setting. They deliberately introduce errors to highlight common pitfalls in organic chemistry. The procedure includes mixing potassium permanganate with sulfuric acid and observing reactions with different organic solvents. Key reactions are monitored for color changes and layer separations, illustrating the distinct reactivity of each compound. The presenter encourages viewers to engage with the results and conduct further research on the reactions observed.

Takeaways

• 😀 The investigation involves deliberately introducing errors to explore error reduction in a lab setting.
• 😀 Safety precautions are emphasized, with all procedures conducted in a fume hood due to the use of organic solvents.
• 😀 The script highlights the importance of labeling test tubes to avoid cross-contamination.
• 😀 Measurements are taken using a pipette and a measuring cylinder for precision.
• 😀 Potassium permanganate is mixed with sulfuric acid, creating a distinct purple solution.
• 😀 The reaction with cyclohexane, toluene, and hexane is observed, noting different reactions and color changes.
• 😀 The script indicates the need to gently shake the test tubes and observe changes in the top layer.
• 😀 After five minutes, the cyclohexane shows a noticeable reaction compared to the other substances.
• 😀 A second experiment with bromine water is set up to further investigate reactivity among the compounds.
• 😀 Observations include the distinct layers of liquids and varying degrees of reactivity indicated by color changes.

Q & A

What is the purpose of conducting the investigation described in the transcript?

The investigation aims to observe and document the reactions of cyclohexane, toluene, and hexane with potassium permanganate and bromine water, while deliberately introducing some errors for educational purposes.

Why is it important to conduct the experiment in a fume hood?

The experiment involves volatile organic compounds that can release harmful fumes, making it crucial to use a fume hood for safety during the handling and mixing of chemicals.

What is the significance of using potassium permanganate in this experiment?

Potassium permanganate is used as an oxidizing agent in the reactions, and its distinct purple color allows for easy observation of any color changes that indicate a reaction has occurred.

What errors were intentionally introduced during the experiment?

The speaker mentioned deliberately making a few errors, such as potential miscalculations in measurements or recording observations, to create examples of possible errors for discussion.

How are the layers formed in the mixtures observed during the experiment?

After adding the potassium permanganate solution to each hydrocarbon, distinct layers are formed due to the immiscibility of the organic solvents with the aqueous solution, which can be visually identified.

What is the expected outcome when cyclohexane reacts with potassium permanganate?

The reaction of cyclohexane with potassium permanganate results in a noticeable color change, indicating oxidation, which may show a transformation from the initial purple color of the permanganate.

What role does bromine water play in the second part of the experiment?

Bromine water is introduced in the second part to test the reactivity of the hydrocarbons, particularly to see if they will decolorize the bromine, indicating the presence of double bonds or reactive sites.

How does the reaction rate of the different hydrocarbons compare?

According to the observations, cyclohexane reacted more quickly compared to toluene and hexane, which was noted through the prompt color change in the reaction with potassium permanganate.

What did the speaker mention about the visibility of reactions after five minutes?

The speaker indicated that after five minutes, the cyclohexane became completely see-through, suggesting a full reaction with potassium permanganate, while the other hydrocarbons retained more of their original characteristics.

What should be recorded during the experiment and why?

Changes in color and the formation of layers in the mixtures should be recorded to provide qualitative data about the reactions and to analyze the effectiveness of each hydrocarbon as a reactant.