IIT JEE , AIEEE Forum - Chemistry , Organic Chemistry - Organic Chem-Assertion Reason

annihilator

ASSERTION:
3 methyl 1 pentene has an asymmetric centre but on hydrogenation the product turns optically inactive.
REASON:
The presence of a chiral carbon is one of the essential conditions for a compound to be optically active.

annihilator

The main problem is that i am doubtful whether we can use the fact that chirality is not necessary for optical activity ,especially since rumours are that JEE is going to be strictly based on NCERT syllabus.

annihilator

hey guys i need some help here....pls

i.rahul.mehra

I think the assertion is true ..reason is true but not the correct explanation of assertion....

sure chirality is not the only criteria for optical activity but it is definitely one of the essentials

annihilator

I agree that its not the only criterion but you see,chirality is not essential for optical activity.For more details www.goiit.com/posts/list/organic-chemistry-chirality-doubt-47227.htm

gagandeep89

the assertion is true reason is false
so it will be c
chirality is one way to check optical activity
there are certainly various compounds which do show optical activity but are not chiral ( in compounds like where there is restricted rotation)

sahilgupta_iit

no annihilator, chirality is necessary condition for a compound being optically active.
the answer to your question is - both assertion and reason are true but reason is not the correct explanation of the assertion.

tarinbansal

I dont think that chirality is one of the essential conditions for optical activity.
It is surely one of the SUFFICIENT conditions but NOT the essential.

Take for example a biphenyl case, such a molecule is optically active(*conditions apply) but it has no chiral centre. So it proves that chirality is NOT ESSENTIAL but a SUFFICIENT condition.

annihilator

Are u guys saying that we can use the fact that chirality is not necessary for optical activity ?Please also take into consideration that JEE is going to be strictly based on NCERT syllabus.

computer001

annihilator:
chirality is necessary but not a chiral carbon...
there is a diff bet the 2 things
even biphenyls and allenes show chirality but they do not have a chiral carbon

annihilator

ok yaar i agree that n all...but the real problem is that since JEE is going to be strictly based on NCERT syllabus can we use this fact.

computer001

yeah v can:
its not given in NCERT syllabus tht chiral carbon is reqd...its mentioned chirality is imp...
and main thing is IIT goes by wats right.. the portion may b based on NCERT but ans is based on wats rite only....

tarinbansal

ya,
computer001 is correct.
IIT goes by what is correct and not by what is given in buks.
There are many misprints and mistakes in ncert but it doesnt mean that just becoz they are given in ncert, IIT will also follow them.

eistien

Assertion and reason are true but is not the right explanation for the assertion

obviously reason is true as it is one of the essential and it is not given it is the essential no???nways whether NCERT is accepted or not this question is free of such problems

the problem arises only when you say it is the essential i hope you understand

then the essential condition will be nonsuperimposability!!!!

computer001

reason is wrong..
chiral carbon is sufficient but it is not essential

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