will'o'wisp
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http://filestore.aqa.org.uk/subjects...4-QP-JUN15.PDF

q10a
never understood this but why can bromine water not test for the double bond in the ketone?
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MexicanKeith
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(Original post by will'o'wisp)
http://filestore.aqa.org.uk/subjects...4-QP-JUN15.PDF

q10a
never understood this but why can bromine water not test for the double bond in the ketone?
An alkene attacks bromine as a nucleophile, because the alkene is electron rich. This makes Bromine the electrophile.

a carbonyl reacts with, for example, cyanide, to form a cyanohydrin. Here the nucleophile is the cyanide and the electrophile is the carbonyl.

so Bromine generally reacts as an electrophile and carbonyls normally react as an electrophile as well.

Electrophile plus electrophile is not a very good recipe for a reaction.
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will'o'wisp
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(Original post by MexicanKeith)
An alkene attacks bromine as a nucleophile, because the alkene is electron rich. This makes Bromine the electrophile.

a carbonyl reacts with, for example, cyanide, to form a cyanohydrin. Here the nucleophile is the cyanide and the electrophile is the carbonyl.

so Bromine generally reacts as an electrophile and carbonyls normally react as an electrophile as well.

Electrophile plus electrophile is not a very good recipe for a reaction.
i c, well thanks!
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MexicanKeith
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(Original post by will'o'wisp)
i c, well thanks!
The test I always mentioned when i was doing A-level for carbonyl was brady's test using 2,4-DNPH.
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