Experiment 4: Reactions of Aliphatic and Aromatic Hydrocarbons by Nurul Izzaty

What we have learned

izzyn0611 — 2024-12-12 03:57:26 UTC

Group 1️⃣

izzyn0611 — 2024-12-12 03:57:26 UTC

Team A

izzyn0611 — 2024-12-12 03:57:26 UTC

Nurul Athirah binti Ariffin Kamal (MS2417120919)

Nurul Izzaty Akhtar binti Syahril Anwar
(MS2418122911)

Team B

izzyn0611 — 2024-12-12 03:57:26 UTC

Leong Zhi Ying (MS2417121685）
Kevin Wong Ken Nam (MS2417121269)

(A) Reaction with bromine in dichloromethane

izzyn0611 — 2024-12-12 03:57:26 UTC

1. 6 dry, clean tubes were labeled as A to F.

izzyn0611 — 2024-12-12 03:57:26 UTC

2. 1 mL of cyclohexane was placed in test tubes A and B, 1 mL of cyclohexene in test tubes C and D, and 1 mL of toluene in test tube E and F.

Observational Data - Team A

izzyn0611 — 2024-12-12 03:57:26 UTC

https://www.canva.com/design/DAGZEGiaRtI/3P9hofTqgZ09r1wintWD4Q/edit?utm_content=DAGZEGiaRtI&utm_campaign=designshare&utm_medium=link2&utm_source=sharebutton

Observational Data - Team B

izzyn0611 — 2024-12-12 03:57:26 UTC

https://www.canva.com/design/DAGZRXz63sI/N3TDtEu3nt7rzU53H074Jg/edit?utm_content=DAGZRXz63sI&utm_campaign=designshare&utm_medium=link2&utm_source=sharebutton

Youtube Experiment Video

izzyn0611 — 2024-12-12 03:57:26 UTC

https://youtu.be/uzME70UbT40?si=0gtxUAd279scksqp

Compare and Contrast Alkanes and Alkenes (10 marks)

izzyn0611 — 2024-12-12 03:57:26 UTC

Similarities:

Both alkanes and alkenes are hydrocarbons
Both alkanes and alkenes are insoluble in water
Both alkanes and alkenes do not conduct electricity
Both alkanes and alkenes have low melting and boiling point

Differences:

Alkanes are saturated but alkenes are unsaturated
Alkanes have single covalent bonds between all the carbon atoms, but alkenes have at least one double covalent bond between two carbon atoms
Alkanes have lower percentage of carbon per molecule, but alkenes have higher percentage of carbon per molecule
Alkanes have less smoky flames, but alkanes have sootier flames
Alkanes undergo free radical substitution reaction, but alkenes undergo electrophilic addition
Cyclohexene can be oxidised by alkaline KMnO4 solution but cyclohexane cannot.

(Individual) All 4 students must submit their discussion separately. Write your name as the subject

izzyn0611 — 2024-12-12 03:57:26 UTC

Analyzing the Outcome

izzyn0611 — 2024-12-12 03:57:26 UTC

You are required to fill in the blanks and make correct equation..

(Group) List two possible sources of error for this experiment

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(Group) Identify two precautions to improve the reliability of the experiment al results

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(Individual) Each student is required to choose 1 of the following and submit their answers separately

izzyn0611 — 2024-12-12 03:57:26 UTC

Write the mechanism of cyclohexane with bromine in the Presence of sunlight. State the function of sunlight in this reaction
Write the mechanism of cyclobutane with bromine in the Presence of sunlight. State the function of sunlight in this reaction.
Write the mechanism of cyclopentane with chlorine in the Presence of sunlight. State the function of sunlight in this reaction.
Write the mechanism of cyclopropane with chlorine in the Presence of sunlight. State the function of sunlight in this reaction.

izzyn0611 — 2024-12-12 03:57:26 UTC

Conclusion

Cyclohexane and toluene undergo free radical substitution reaction with bromine in the presence of sunlight.
Cyclohexene undergoes electrophilic addition with bromine in sunlight with or without the presence of sunlight.
Cyclohexene can be oxidised by alkaline KMnO₄ solution whereas cyclohexane and toluene cannot be oxidized.

(Group)

izzyn0611 — 2024-12-12 03:57:26 UTC

Research: Use the internet to find at least one real-life example or application for each reaction:
- Free Radical Substitution of Alkanes
- Electrophilic Addition of Alkenes
Include Details: For each example, provide the following:
- A brief description of the application or process (e.g., where and how the reaction is used).
- The chemical involved in the reaction and its significance.
- If possible, mention the industry or product that uses this reaction (e.g., pharmaceuticals, polymers, etc.).
Visuals:
- Add relevant images, diagrams, or videos to support your examples.
- Ensure the visuals are clear and appropriately credited (if taken from online sources).

Question 1

bhmcnjq7w2 — 2024-12-12 04:16:54 UTC

The purpose of bromine test (Br in CH,Cl,) is to differentiate between saturated and unsaturated hydrocarbon.

Question 2

m7628485 — 2024-12-12 08:00:59 UTC

The function of potassium permanganate is to act as oxidizing agent.

Question 3

athirahak — 2024-12-12 08:03:17 UTC

Place cyclohexane and cyclohexene in the ice bath is not the safety precaution of the experiment.

Question 4

athirahak — 2024-12-12 08:03:45 UTC

The positive result for the reaction of alkene with cold alkaline solution of potassium permanganate, KMnO4 is where the purple solution is decolourised.

Question 5

athirahak — 2024-12-12 08:04:01 UTC

The type of reaction between cyclohexane and bromine in dichloromethane is free radical substitution reaction.

athirahak — 2024-12-14 12:10:49 UTC

Dropper

Test tube

Rubber band

Labelling paper

Test tube rack

Black sugar paper (6 cm x 12 cm)

athirahak — 2024-12-14 12:12:57 UTC

Toluene

Athirah

athirahak — 2024-12-14 12:17:11 UTC

(A) Reaction with bromine in dichloromethane

Cyclohexane is a saturated hydrocarbon that undergoes free radical substitution reaction in the presence of sunlight. Sunlight provides energy for homolytic cleavage of halogens to form free radicals.

Cyclohexene is an unsaturated hydrocarbon that undergoes electrophilic addition reaction in the presence of sunlight.

Toluene contains a methyl group that undergoes free radical substitution reaction in the presence of sunlight.

(B) Oxidation with cold alkaline solution of KMnO₄ (Baeyer's test)

Baeyer's test is a confirmatory test for alkenes, so only alkenes show positive result.

Izzaty

athirahak — 2024-12-14 12:17:25 UTC

(A) Reaction with bromine in dichloromethane

Cyclohexane is a saturated hydrocarbon that undergoes free radical substitution reaction in the presence of sunlight.Sunlight provides UV ray for homolytic cleavage of halogens to form free radicals.

Cyclohexene is an unsaturated hydrocarbon that undergoes electrophilic addition reaction with or without the presence of sunlight.

Toluene contains a methyl group that undergoes free radical substitution reaction in the presence of sunlight.

(B) Oxidation with cold alkaline solution of KMnO₄ :

Baeyer's Test is a confirmatory test for alkenes, so only alkenes show positive result.

Leong

athirahak — 2024-12-14 12:17:38 UTC

A) Reaction with bromine in dichloromethane

Cyclohexane is a saturated hydrocarbon that undergoes free radical substitution reaction in the presence of sunlight (UV).

Sunlight provides energy for homolytic cleavage of halogens to form bromine free radicals.

Cyclohexene is an unsaturated hydrocarbon that undergoes electrophilic addition reaction with or without the presence of sunlight.

Toluene contains a methyl group that undergoes free radical substitution reaction in the presence of sunlight (UV).

(B) Oxidation with cold alkaline solution of KMnO₄ (Baeyer's test)

Baeyer's test is a confirmatory test for alkenes, so only alkenes show positive result.

Kevin

athirahak — 2024-12-14 12:17:49 UTC

(A) Reaction with bromine in dichloromethane

Cyclohexane is a saturated hydrocarbon that undergoes free radical reaction in the presence of sunlight. Sunlight provides UV rays for homolytic cleavage of halogens to form bromine radicals.

Cyclohexene is an unsaturated hydrocarbon that undergoes electrophilic addition reaction in the presence of sunlight.

(B)Oxidation with cold alkaline solution of KMnO₄(Baeyer's Test)

Baeyer's test is a confirmatory test for alkenes, so only alkene shows positive result.

Athirah

athirahak — 2024-12-14 12:19:20 UTC

Izzaty

athirahak — 2024-12-14 12:19:34 UTC

Sunlight breaks down the bromine molecule into free radicals.

Leong

athirahak — 2024-12-14 12:19:42 UTC

Sunlight provides the energy (UV light) necessary for the homolytic cleavage of the bromine molecule in the initiation step.

Kevin

athirahak — 2024-12-14 12:19:49 UTC

Sunlight in the form of UV ray provides energy for homolytic cleavage of bromine molecules to form bromine radicals.

Example of free radical substitution of alkanes

athirahak — 2024-12-14 12:24:24 UTC

Reaction between methane and chlorine in the presence of UV light :

CH₄ + Cl₂ ---> CH₃Cl + HCl

Application of free radical substitution of alkanes

athirahak — 2024-12-14 12:25:07 UTC

Manufacture of halogenated alkanes: Used in creating solvents, refrigerants, and in the pharmaceutical industry.
A cornerstone in organic synthesis: The reaction is fundamental in the synthesis of a wide array of organic compounds.

Example of electrophilic addition of alkenes

athirahak — 2024-12-14 12:25:44 UTC

When cyclohexene reacts with hydrogen bromide. The double bond breaks and a hydrogen atom ends up attached to one of the carbons and a bromine atom to the another atom.

Application of electrophilic addition of alkenes

athirahak — 2024-12-14 12:26:27 UTC

The hydrochlorination of alkenes, such as ethene with HCl, leads to the formation of vinyl chloride, the monomer for producing polyvinyl chloride (PVC).
PVC is a widely used plastic in construction materials (pipes, flooring, window frames), medical devices, packaging, and clothing. The production of PVC relies on the electrophilic addition of HCl to ethene.

Precaution steps

athirahak — 2024-12-14 12:31:16 UTC

1. Make sure the test tubes are fully dry before conducting the experiment

2. Always keep the reagent bottles closed due to cyclohexane & cyclohexene are volatile compounds

Sources of error

athirahak — 2024-12-14 12:32:23 UTC

1. The test tubes were not fully dry before use

2. Long queue in front of the fume cupboard

athirahak — 2024-12-14 12:47:44 UTC

1. https://www.tutorchase.com/notes/cie-a-level/chemistry/14-1-3-free-radical-substitution-in-alkanes

athirahak — 2024-12-14 13:19:25 UTC

3. Test tubes A, C and E were wrapped with black sugar papers.

athirahak — 2024-12-14 13:20:25 UTC

4. 4 to 5 drops of 4% bromine in dichloromethane were added into each test tubes.

athirahak — 2024-12-14 13:22:05 UTC

5. Test tubes A, C and E were kept in a dark place, and test tubes B, D and F were kept in the sunlight. They were left for 15 minutes.

6. Observations were recorded.

(B) Oxidation with cold alkaline solution of KMnO4 (Baeyer's Test)

athirahak — 2024-12-14 13:23:28 UTC

1. Dry, clean test tubes were labeled as G,H and I.

athirahak — 2024-12-14 13:24:12 UTC

2. 1 mL of each cyclohexane, cyclohexene and toluene was placed in test tubes G, H and I, respectively.

athirahak — 2024-12-14 13:27:09 UTC

3. A few drops of alkaline KMnO4 solution were added into each test tube and were shaken.

4. The observations were recorded.

athirahak — 2024-12-14 13:33:59 UTC

2. https://www.chemguide.co.uk/mechanisms/freerad/whatis.html#:~:text=A%20simple%20example%20of%20substitution,UV%20light%20(or%20sunlight).&text=Notice%20that%20one%20of%20the,That's%20substitution.

athirahak — 2024-12-14 13:34:10 UTC

3. https://youtu.be/SnJkPhGQ74s?si=oBLvyUNP2hnf1SfO

athirahak — 2024-12-14 13:34:21 UTC

4. https://chem.libretexts.org/Bookshelves/Organic_Chemistry/Book%3A_Organic_Chemistry_with_a_Biological_Emphasis_v2.0_(Soderberg)/14%3A_Electrophilic_Reactions/14.02%3A_Electrophilic_Addition_to_Alkenes

athirahak — 2024-12-14 13:34:33 UTC

5. https://youtu.be/z5hQ8iZZ8dU?si=6F5ZNDkZRX9BcQFh

athirahak — 2024-12-14 13:34:48 UTC

6. https://en.wikipedia.org/wiki/Aliphatic_compound

izzyn0611 — 2024-12-27 08:56:28 UTC

Cyclohexane

izzyn0611 — 2024-12-27 08:57:17 UTC

Cyclohexene

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Alkaline

izzyn0611 — 2024-12-30 07:36:05 UTC

4% bromine in dichloromethane

izzyn0611 — 2025-01-01 14:43:43 UTC

izzyn0611 — 2025-01-01 14:43:58 UTC