• # question_answer 58)   The molecules having dipole moment are.......... (a) 2, 2-Dimethylpropane                                             (b) trans-Pent-2-ene (c) cis-Hex-3-ene                                                             (d) 2, 2, 3, 3-Tetramethylbutane

(b, c) Since the $+I$ effect of $C{{H}_{2}}C{{H}_{3}}$ group is higher than that of$C{{H}_{3}}$ group, therefore, the dipole moment $C-C{{H}_{3}}$ and$C-C{{H}_{2}}C{{H}_{3}}$ bonds are unequal. Although these two dipoles oppose each other, yet they do not exactly cancel out each other and hence trans-2-pentene has small but finite dipole moment. In cis-hex-3-ene, although the dipole moments of the two $C-C{{H}_{2}}C{{H}_{3}}$ bond are equal, but are inclined to each other at an angle of $60{}^\circ$ and hence have a finite dipole moment.