Discussion Forum



1)

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


A) 274,0.00

B) 277,0.00

C) 277,0.33

D) 274,0.33

Answer:

Option B

Explanation:

1072021776_m19.PNG

Boiling point =$37^{0}C(\approx$277k)

$\mu=0.33D$

 cis-but-2ene has higher dipole-dipole attraction than trans-isomer hence, has high boiling point.

1072021839_m20.PNG

Boiling point=0.9= ° C( $\approx$ 274 K)

 $\mu=0D$

  the dipole moment of trans-but-2ene is zero because the bond dipoles cancel each other.

However, the dipole moment of cis-but-2-ene  is 0.33 D , the vector  sum of the two bond dipoles