Tricky ochem Q

[cloak25]

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Passage states that "a positive test with bromine in CCl4 indicates the presence of an alkene."

A compound that turns clear (positive) with Br2/CCl4 and has one degree of unsaturation CANNOT be:

A. a ketone
B. an alkene
C. an ether
D. an alcohol

TBR's explanation for this was kind of confusing. Anyone want to take a stab at explaining this?

Edit: answer is: A

 

[EnginrTheFuture]

A. Reason being is you only have 1 unit of unsaturation present (only 1 double bond).

If you have tht double bond as a carbonyl C=O then there is no way you have a C=C because there's only one double bond and it is to the oxygen. The BR2 test tests for C=C so an alcohol could have a C=C-OH and ether can have C=C-O-R and of course and alkene has a C=C... The only one that can't have a C=C is the one that have a C=O already

 

[MedPR]

Passage states that "a positive test with bromine in CCl4 indicates the presence of an alkene."

A compound that turns clear (positive) with Br2/CCl4 and has one degree of unsaturation CANNOT be:

A. a ketone
B. an alkene
C. an ether
D. an alcohol

TBR's explanation for this was kind of confusing. Anyone want to take a stab at explaining this?

Edit: answer is: A

One degree of unsaturation = one pi bond or one ring. A ketone with only one degree of unsaturation cannot also have an alkene functional group.

 

[cloak25]

Guess it wasn't so tricky after all. 😳

 

[MedPR]

Guess it wasn't so tricky after all. 😳

It's hard if you don't read carefully 😀. Take your time through the questions; it really helped me.