The boiling poing (in K) of cis but -2- ene and dipole moment ( in D) of trans but -2- ene are respectively

Options

A. 274,0.00
B. 277,0.00
C. 277,0.33
D. 274,0.33

Answer

B

Explanation

Boiling point`=3.7^@C(approx277K)
mu=0.33D`
cis-but-2-ene has higher dipole-dipole attraction than trans isomer hence, has high boiling point.

Boiling point`=0.9^@C(approx274K)`
`mu=0D`
The dipole moment of trans-but-2-ene is zero, because the bond dipoles cancel each other.
However, the moment of cis-but-2-ene is 0.33D, the vector sum of the two bond dipoles.