destroyer ochem#112

[reztab]

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It says CH3_CH=CH=CH(CH3)_C2H5 is optically active, but I cannot find any chiral carbon. plz help

 

[PhansterZ]

It says CH3_CH=CH=CH(CH3)_C2H5 is optically active, but I cannot find any chiral carbon. plz help

That molecule doesn't exist. You have a 2 carbons with 5 bonds...

Wanna draw it out on paint and upload it?

 

[PhansterZ]

It says CH3_CH=CH=CH(CH3)_C2H5 is optically active, but I cannot find any chiral carbon. plz help

I hope you mean ...

(CH3)CH=C=C(CH3)(C2H5)

In this case , the molecule is chiral because of the orientation of the groups. The two double bonds will make the groups on each side perpendicular to each other. Since you cannot draw a line to divide this molecule in half, it will be chiral. This is a special case of chirality though, as it does not contain any chiral carbons, but... the entire molecule would be considered chiral.

 

[nimman1126]

Curious, where did this question come from? Also is it likely to be tested on the DAT because its one of those few exceptions that hasnt been covered?

 

[bharat008]

Curious, where did this question come from? Also is it likely to be tested on the DAT because its one of those few exceptions that hasnt been covered?

There are only 2 exceptions when it comes to chirality...
The compound shown here is called ALLENE, which is chiral (exception)
Another exception is BIPHENYL; which is also chiral...

 

[Troyvdg]

It says CH3_CH=CH=CH(CH3)_C2H5 is optically active, but I cannot find any chiral carbon. plz help

the pi orbitals have to be perpendicular to each other in order to have two double bonds to the same carbon 👍 as the poster above me said, its an exception

 

[pksatodia]

It says CH3_CH=CH=CH(CH3)_C2H5 is optically active, but I cannot find any chiral carbon. plz help

One more exception: All Allenes are not chiral
Example: H2C=C=CH(CH3), since there are same atom to one of carbon center. Thus in this example, compound is not chiral.

All in all be careful of such tricky question 😀

 

[pksatodia]

Other thing refer to Chad's videos, he explains it much better and in a little detail on why.

me explained vaguely😀