[jena]

Hi,

I have two question one regarding tortional strain the other, stability.

Q 1. Which cycloalkane ahs the least tortional strain

a. cyclopropane
b. cyclobutane
c. cyclopentane
d. cyclohexane
e. cycloheptane

My answer: c. cyclopentane

Q2. Which isomer is the least stable?

a. cis-1,2-dimethylcyclohexane
b. trans-1,2-dimethylcyclohexane
c. cis-1,3-diemethylcyclohexane
d. trans-1,4-dimethylcyclohexane
e. not a.-d.

My answer: b.

Are my answer correct or should I look over them one more time.

Thank You  

[dexangeles]

Q1 id say D

torsional strain is usually defined on eclipse vs staggered conformations
cyclohexane is capable of forming a chair conformation which makes all the angles of the bonds staggered.  If I remember right, the torsional strain on the chair conformation of cyclohexane is 0


Q2 my answer is A

1 methyl in axial and 1 methyl in equatorial
unlike B,C,D all the methyls are in the equatorial position which makes it more stable
remember: equatorial position is more stable than axial