Lab Report on Hydrocarbons

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[pic 7]

Aromatic hydrocarbons are unreactive with bromine without a catalyst and resulted in the dilution of the color of bromine to orange to yellow.

Unwrapped test tube with toluene reacted with Br because it is light initiated.

Oxidation: Reaction with Baeyer’s Reagent

Dilute aqueous potassium permanganate oxidizes alkenes (cyclohexene) to geminal diols. Under more vigorous conditions the geminal diol (from an alkene) that is initially produced will be further oxidized by the permanganate, producing more manganese dioxide.[pic 8]

Treatment of an alkylbenzene with potassium permanganate results in oxidation to give the benzoic acid. The reaction only works if there is a hydrogen attached to the carbon.

[pic 9]

Alkyl groups are usually fairly resistant to oxidation. However when they are attached to a benzene ring, they are easily oxidized by . [pic 10]

Alkanes and aromatic rings are unreactive toward dilute aqueous potassium permanganate because they are highly stable

Reaction with Ammoniacal [pic 11]

When ammoniacal was added to cyclohexane, the solution became cloudy. Same as when was added to cyclohexene. Ammoniacal will only react with Alkynes leading to the release of the terminal proton of the alkyne so that the resulting acetylide ion can form an insoluble precipitate with Ag+. Acetylene reacts with ammoniacal solution of forming acetylide of silver. [pic 12][pic 13][pic 14][pic 15]

Preparation of Acetylene Gas

Acetylene formed when water reacts with calcium carbide.

[pic 16]

- Conclusion

Hydrocarbons can be known and be differentiated by their physical properties and chemical reactivity. According to their solubility, these hydrocarbons are insoluble; immiscible to water as they are nonpolar substances as opposed to the high polarity of water. The densities are the same for each with the exception chlorobenzene due to the hydrogen bonds that have to be broken, the dispersion forces that are acting upon the molecule as opposed to making new bonds in reacting water with chlorobenzene. These hydrocarbons also react with concentrated . Solution although insoluble forming hydrogen bonds to the hydrocarbons. Even aromatic compounds also react with conc. . As it undergoes a substitution reaction. Alkanes are unreactive to bromine unless under special condition or catalyst like being exposed to UV light also alkanes are unreactive to potassium permanganate. Alkenes are readily reactive to bromine since its double bonds can be broken easily though addition reaction also is relatively similar if alkenes are added to potassium permanganate. Aromatic compounds are unreactive because they are usually stable and can only be reacted if given a catalyst. [pic 17][pic 18]

References:

- http://documents.tips/documents/final-report-experiment-7-preparation-and-characterization-of-hydrocarbons.html

- http://employees.oneonta.edu/knauerbr/chem226/226expts/226_expt03_pro.pdf

- https://www.slideshare.net/joicesanluis/hydrocarbons-27066904

- https://www.slideshare.net/sheleylovin/preparation-and-properties-of-acetylene