Reaction between Bromine and Cyclohexane

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rollingstome
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#1
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I've been given some questions about the reaction between bromine and cyclohexane, and one that slightly threw me was:

'Why is water added to the reaction mixture (bromine + cyclohexane), even though it is not a reactant?'

It's probably something pretty simple I'm missing, does anyone have any ideas?
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charco
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(Original post by rollingstome)
I've been given some questions about the reaction between bromine and cyclohexane, and one that slightly threw me was:

'Why is water added to the reaction mixture (bromine + cyclohexane), even though it is not a reactant?'

It's probably something pretty simple I'm missing, does anyone have any ideas?
Bromine reacts with cyclohexane in the presence of UV light. There is no water needed.

Are you sure that you don't mean 'cyclohexene'?
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rollingstome
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(Original post by charco)
Bromine reacts with cyclohexane in the presence of UV light. There is no water needed.

Are you sure that you don't mean 'cyclohexene'?
It definitely says cyclohexane! I thought water might be added to ionise the bromine, to form bromine water, which then reacts with the cyclohexane?
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TimmsElJefe
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Which state was the Bromine in, gaseous or aqueous? Because I'm thinking that the water dissolves the Bromine which then reacts with Cyclohexane and forms two separate layers, both of which should be an orange colour.
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rollingstome
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(Original post by TimmsElJefe)
Which state was the Bromine in, gaseous or aqueous? Because I'm thinking that the water dissolves the Bromine which then reacts with Cyclohexane and forms two separate layers, both of which should be an orange colour.
We just used bromine water in the practical, so it must have already been dissolved in the water. Thanks so much for your help!

Though just a question about the layers, would bromocyclohexane be in the top or bottom layer?
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charco
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(Original post by rollingstome)
We just used bromine water in the practical, so it must have already been dissolved in the water. Thanks so much for your help!

Though just a question about the layers, would bromocyclohexane be in the top or bottom layer?
Bromine does not react with cyclohexane (without UV light) with or without water!

Wait a minute...

.. a thought occurs to me.

You are not reacting bromine with cyclohexane, you are DISSOLVING bromine in cyclohexane and water mixed.

This shows two layers with slightly different colours demonstrating that bromine is more soluble in non-polar solvents.
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TimmsElJefe
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(Original post by rollingstome)
We just used bromine water in the practical, so it must have already been dissolved in the water. Thanks so much for your help!

Though just a question about the layers, would bromocyclohexane be in the top or bottom layer?
You're welcome, although you don't get bromocyclohexane because it doesn't react with Bromine, it only dissolves in the layer. The top layer is Cyclohexane and the bottom layer is water.

Hope this helps!
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rollingstome
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(Original post by charco)
Bromine does not react with cyclohexane (without UV light) with or without water!

Wait a minute...

.. a thought occurs to me.

You are not reacting bromine with cyclohexane, you are DISSOLVING bromine in cyclohexane and water mixed.

This shows two layers with slightly different colours demonstrating that bromine is more soluble in non-polar solvents.
(Original post by TimmsElJefe)
You're welcome, although you don't get bromocyclohexane because it doesn't react with Bromine, it only dissolves in the layer. The top layer is Cyclohexane and the bottom layer is water.

Hope this helps!
Thanks for your help!
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#minniemouse
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(Original post by charco)
Bromine reacts with cyclohexane in the presence of UV light. There is no water needed.

Are you sure that you don't mean 'cyclohexene'?
What would be the balance equation for the reaction between aqueous bromine cyclohexane and cyclohexene
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