The molecules having dipole moment are ________

1. 2,2-Dimethylpropane

2. trans-Pent-2-ene

3. cis-Hex-3-ene

4. 2,2,3,3 - Tetramethylbutane

(2, 3)
Thus, trans-pent-2-ene show net dipole moment because different group attached and cis-Hex-3-ene show dipole moment because both groups $\left({\mathrm{C}}_{2}{\mathrm{H}}_{5}\right)$ are inclined to each other to angle of $60°$ therefore have a finite resultant.