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Reactions of 3 Hydrocarbons: Cyclohexane, Cyclohexene and Toluene


it looks lilke a lot to read but it all comes together quickly. The actual experiment has already been performed and the results have been recorded in the table (last page). Please look at what is in RED color - that is what needs to be answered in a more elaborated conclusion/lab report form (but it doesn't have to be extensive at all...) Also, on the data sheet, please feel free to add any information - or make any corrections - based on your knowledge of these types of reactions with these particular hydrocarbons.

Thank you!

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Welcome to BrainMass. Let's see if I can help you interpret the results of this experiment, one part at a time.

A. Reaction of hydrocarbons with bromine: Bromine is a reddish brown liquid, so if it reacts with another chemical, the initial red color will disappear (or at least fade). Based on the results you reported, you misunderstood this somewhat. The procedure was a little vague about how to recognize a reaction (although the background explained it better).
Immediate results-
Cyclohexane: Red color remained: No reaction.
Cyclohexene: Red color disappeared immediately: Immediate reaction.
Toluene: Your observations are not clear. Did the red bromine gradually fade to yellow, or was it yellow from the start? There are two possibilities: The bromine and toluene reacted partially, leaving only some yellow color instead of a strong red, OR you accidentally added too little bromine. IF you are 100% certain that you added the proper amount of bromine, then it is safe to infer that a some reaction occurred- in other words, the bromine and toluene reacted together, but much more slowly than the Br2 and cyclohexene.
There was a second part of this experiment but I can't tell if you performed it. The procedure tells you that if no reaction occurs (i.e., if some color remains) then you should put the unreacted samples in sunlight near a window. This may not have been possible if the lab was performed at night, for example.
If you HAD done this, you probably would have seen the red color in the cyclohexane and toluene slowly fade. It turns out that exposure to light speeds up bromine's ...

Solution Summary

Reactions of three hydrocarbon, cyclohexane, cyclohexene and toluene, are examined.