Orders

Question 1

Which one has the highest dipole moment among: NF₃ , BF₃ and NH₃

Answer 1

NH₃ > NF₃ > BF₃

Question 2

Greatest dipole?

NHF₂ , NF₃ , NH₂F , NH₃

Answer 2

NH₃ > NH₂F > NHF₂ > NF₃

trend explanation: number of EN atoms increases, dipole moment decreases.

Question 3

Give the ascending order of dipole moment:

CH₂Cl₂ , CHCl₃ , CH₃Cl , CCl₄

Answer 3

CCl₄ < CHCl₃ < CH₂Cl₂ < CH₃Cl

Question 4

dipole moment order:

p- dichlorobenzene, o-dichlorobenzene, m-dichlorobenzene

Answer 4

ortho > meta > para

as long as the same group has been substituted twice

Question 5

dipole moment order:
o-hyrdoxynitrobenzene, p-chloronitrobenzene, m-chloronitrobenzene.
Explain.

Answer 5

para > meta > ortho

Since both the groups attached have opposite natures of donating (OH⁻) and receiving electrons (NO₂⁻), here, in para instead of cancelling, they get added up and the bond angle reducing counters the effect of both vectors were getting added up.

Question 6

dipole moment order: cis-1-chloropropene, trans-chloropropene

Answer 6

Usually, trans has lesser dipole moment since the substituted groups occupy opposite positions and get cancelled. We observe an exit from this trend both the groups (Cl⁻ withdrawing) and (CH₃- alkyl, donating) have opposite natures and in trans form, instead get added up.

Question 7

Why do p-dihydroxybenzene and p-dimethoxybenzene have non-zero dipole moment while p-dichlorobenzene and p-dicyanobenzene have zero dipole? discrimimation.

Answer 7

planal symmetry of a compound plays an important role in determining its dipole moment.
Since here same groups are substituted on the benzen ring, we can say that symmetry reduces (in para sometimes to zero too) the dipole moment owing to its vector nature.

here, by principle, the atom direclty attached to the carbon of benzene lies in its plane (p-dichloro and -CN because it has a triple bond, linear and therefore N too lies in the same plane). in the other, the H- and alkyl groups do not lie in the same plane and contribute to the overall dipole.

Question 8

In PCl₃F₂ , which atoms occupy the axial positions?

Answer 8

Fluorine. Axial position is alloted to more EN atoms so that there is minimum repulsion since distance is more.

Question 9

What do XeF₄ , 1,3,5- trichlorobenzene, p-dichlorobenzene have in common?

Answer 9

Z e r o D i p o l e M o m e n t