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Topic: cyclohexane and bromine water  (Read 9517 times)

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Offline davon806

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cyclohexane and bromine water
« on: September 30, 2012, 10:50:28 AM »
I have done an experiment several weeks ago.Cyclohexane was used to test the chemical properties of alkanes.
Under UV light,when cyclohexane is added to bromine water,the solution will not decolorize.
However,I remember some books said that when hexane is added to bromine water under the same condition,the red-orange colour of bromine is discharged.
Why?

Offline discodermolide

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Re: cyclohexane and bromine water
« Reply #1 on: September 30, 2012, 12:22:37 PM »
Do you not find this strange? I mean cyclohexane and hexane are quite inert hydrocarbons. I don't think hexane will decolourise bromine water even under UV light.
Are you sure it is hexane could it be that the book said hexene? (I know books don't talk).
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Offline davon806

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Re: cyclohexane and bromine water
« Reply #2 on: September 30, 2012, 01:34:57 PM »
yes.It is hexane,please see the attached.

Offline discodermolide

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Re: cyclohexane and bromine water
« Reply #3 on: September 30, 2012, 02:06:58 PM »
Then the UV light is generating radicals, Br. and HO.
These the abstract a H radical from hexane, probably to give water, And a C6H13 radical which then reacts with the bromine radical to give C6H13Br.
But I would expect the same to happen with cyclohexane. This is somewhat puzzling.
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Offline curiouscat

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Re: cyclohexane and bromine water
« Reply #4 on: September 30, 2012, 02:13:01 PM »
yes.It is hexane,please see the attached.

Bromine is different from Bromine Water.

Offline davon806

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Re: cyclohexane and bromine water
« Reply #5 on: September 30, 2012, 02:38:41 PM »
Re curiouscat.
What is the difference?
Either water or organic solvent will not participate in the reaction.
I think we use bromine water just because of safety?And the final result should be the same as using pure bromine?

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