A. Thermal Expansion
Hope this helps :)
If the totaling of bromine to cis-cinnamic acid uses the
same mechanism or device as the addition to trans-cinnamic acid, addition of
bromine only transpires on the top (syn) and not the bottommost face (anti). Therefore,
bromine added to cis-cinnamic only adds to the same face (syn addition) as a
result producing only threo dibromides.
The answers is B that’s your answer
No, molecules don’t ever stop moving
