Test: Dipole Moment - NEET MCQ

In a given structure there are 4 -pi bonds.Hence, total number of pi electrons are 8.

Bond length and (EN) oppose each other, with the larger halogens having longer bonds but weaker (EN). Thus CH₃CI > CH₃F > CH₃Br.

Toluene with one —CH₃ is less polar then m - and o-dichlorobenzene. Thus, IV < l < III < II.

 If one considers following molecule, it is 

Symmetrical and thus
In the given species

Larger the value of θ, smaller the value of μ. Dipole-dipole repulsion (due to large groups (as Cl, Cl) increases , thus decreases p.
Intramolecular H-bonding (as OH and NO₂) decreases θ, thus increases μ.

Repulsion
(Cl—Cl) > (OH—OH) > (CH₃—CH₃)
Thus, μ is minimum when X = V = Cl and μ is maximum when X = OH
Y = NO₂

Carbon dioxide CO₂ has polar bonds but is a nonpolar molecule. The structure of CO₂ is linear. The individual bond dipoles cancel each other as they point in opposite direction and are equal in magnitude. Hence, the molecule is non polar with zero dipole moment.

The Phosphorus Pentafluoride (PF₅) is a nonpolar molecule because the configuration of PF₅ has trigonal bipyramidal, and PF₅ consists of a central phosphorus atom, surrounded by five fluorine atoms. So the three planar fluorine’s electronegativity cancels out each other, which resulting PF₅ is a nonpolar molecule.

similarly, in PCl₅ case chlorine's electronegativity cancels out each other.

 In case of PCl_3​F₂​, the molecule is non-polar, even though the fluorine atoms are slightly more electro-negative than the chlorine. This could be explain in a couple ways. The more intuitive approach is to consider how the presence of two fluorine atoms would create symmetry. The less intuitive, but more accurate, process would be to realize that the structure of the molecule is divided in to two non-polar structure(trigonal planer and linear). With other molecules, like PF₃​Cl₂​ it's not possible to divide it in to non-polar shapes. The repulsion between the fluorine atom is greater than that between the chlorine. Thus PF_3​Cl_2​ is polar.

van der Waals` force is the weakest force of attraction and covalent bond is the strongest. Correct order is 

(c) SF₄ has one lone pair making it polar permanently.

sp³d-hybridised S-atom.
(d) XeF₄ has two lone pairs in opposite side thus μ = 0 

CO, SO₂, H₂O, NH₃ and HCI have polarity thus, have dipole moments.

Resultant dipole moment of CCI₄ = 0.

 has one unpaired electron in unhybridised p-orbital.
Thus, sp²-hybridised paramagnetic.

Due to electronegativity difference between the bonded atoms. ICI, NO, SO₂, CH₂CI₂, OCS are polar compounds.

CH₂CI₂,H₂O,CHCI₃,o-cresol, SCI₂, IBr and HCHO (in all seven) have dipole moments.