Stereogenic carbons & Cis/trans isomers

[SargeX_au]

Hey, i have 2 questions.

1. C5H4-C*H(Cl)CH3

Is the stereogenic carbon atom in this the one of the left, does it have four different groups attached to it?....Or is it the one on the right?

 

2. For a pair of cis-trans isomers, would reaction rates with achiral reactants be the same?

Also, would the sign or magnitude of optical rotation be the same for a pair of cis-trans isomers?

THX.

[rakuenso]

for Q1 are you asking for chirality centers?

 

For Q2 I think it depends on the isomer,

 

I don't think the optical rotations are the same for a trans-isomers as opposed to a cis-isomer. They are diastereisomers. If the cis-isomer is achiral, then you wouldn't get any optical activity. But if the trans is chiral, then you would. So i guess thats your answer. (Btw is there such a thing as an achiral trans isomer with a chiral cis isomer?)

[SargeX_au]

1. The question orginally was, circle a stereogenic carbon atom in this molecule.

_

/ \ _CH(Cl)CH3 (thats meant to be a pentagon connecting to the CH)

\ /

 

2. Yeh i'm pretty sure there is no similarity for the sign or the magnitude of optical rotation for cis-trans isomers. So the only part i'm confused about now is whether "reaction rates which achiral reactants" would be the same for a pair of cis-trans isomers.

[rakuenso]

cis-trans isomers can't be both be achiral

[SargeX_au]

i'm confused