The incorrect statement regarding the geometrical isomers of 2-butene is :

Solution

Chemistry ma’am · 3 steps

Draw both isomers and add the bond dipoles: in trans they cancel, in cis they add.

1. What geometrical isomers are. In 2-butene, each double-bonded carbon carries one CH₃ and one H. The two isomers have the same connectivity and differ only in arrangement in space, so they are stereoisomers.
2. Check dipole moment. Each C-CH₃ bond has a small bond dipole. In trans-2-butene the two methyl groups sit on opposite sides, so these dipoles point in opposite directions and cancel, giving μ ≈ 0. In cis-2-butene both methyls are on the same side, so the dipoles add to a small net value.

   Statement	True or false	Reason
   (a) Not interconvertible at room temperature	True	Rotating about C=C means breaking the π bond, which needs far more energy than room temperature supplies
   (b) trans more stable than cis	True	In cis the two bulky CH₃ groups crowd each other on the same side, which causes steric strain
   (c) cis has less dipole moment than trans	False	cis has the larger dipole moment; in trans the bond dipoles cancel to nearly zero
   (d) They are stereoisomers	True	Same atoms, same bonds, different spatial arrangement

3. So. Statement (c) has the comparison backwards. cis-2-butene has the higher dipole moment, so (c) is the incorrect statement.

The idea to keep. For cis and trans alkenes with identical groups, trans is usually more stable and has the lower dipole moment, often zero, because its bond dipoles point opposite ways and cancel.

Answer from the NTA final answer key. Solution by PrepWiser.