Out of the following compounds , which will be have a zero dipole moment.

Question

(a) 1,1 - dichloroethylene (b) cis-1,2-dichlorethylene c)trans-1,2-dichlorethylene d) none of these.

Answer 1

In case of trans-1,2-dichloroethylene

http://clay6.com/mpaimg/jee%20c%2041.JPG

The net dipole moment is zero but in case of cis -1,2 -dicholorethylene.

There is some resultant dipole moment.

Hence c is the correct answer.