Chemical Bonding and Molecular Structure Test 13

Result

Chemical Bonding and Molecular Structure Test 13

Score
-
out of -
Rank
-
out of -

TIME Taken - -

SHARING IS CARING

If our Website helped you a little, then kindly spread our voice using Social Networks. Spread our word to your readers, friends, teachers, students & all those close ones who deserve to know what you know now.

Weekly Quiz Competition

Question 1
1 / -0

Direction (Q. Nos. 1-11) This section contains 12 multiple choice questions. Each question has four choices (a), (b), (c) and (d), out of which ONLY ONE option is correct.
Number of π bonds in the following structure is–

A
4

B
20

C
19

D
8

Solution

In a given structure there are 4 -pi bonds.Hence, total number of pi electrons are 8.
Question 2
1 / -0

Correct decreasing order of dipole moment of CH₃F, CH₃CI and CH₃Br is

A
CH₃F > CH₃CI > CH₃Br

B
CH₃F > CH₃Br > CH₃C

C
CH₃CI > CH₃F > CH₃Br₂

D
CH₃CI > CH₃Br > CH₃F

Solution

Bond length and (EN) oppose each other, with the larger halogens having longer bonds but weaker (EN). Thus CH₃CI > CH₃F > CH₃Br.
Question 3
1 / -0

Consider the following compounds
Q. Increasing order of dipole moment of these compounds is

A
I < II < III < IV

B
IV < III < II < I

C
IV < I < III < II

D
IV < II < I < III

Solution

Toluene with one —CH₃ is less polar then m - and o-dichlorobenzene. Thus, IV < l < III < II.
Question 4
1 / -0

Dipole moment of is 1.5 D. Thus, dipole moment

A
0.00 D

B
1.5 D

C
2.0 D

D
3.0 D

Solution

If one considers following molecule, it is

Symmetrical and thus
In the given species
Question 5
1 / -0

Given for HCI and HI
Q. Ratio of fraction of electric charge existing on each atom in HCI and HI is

A
1.2:1

B
2.7:1

C
3.3:1

D
1:3.3

Solution
Question 6
1 / -0

Ortho-isomers have dipole moments. In which cases dipole moments are maximum and minimum?

A
a

B
b

C
c

D
d

Solution

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
Question 7
1 / -0

Which of the following is nonpolar but contains polar bonds?

A
CO₂

B
HCl

C
NH₃

D
NO₂

Solution

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.
Question 8
1 / -0

Bond length of H— Cl is 1.2476 Thus, its dipole moment is

A
6.0 D

B
1.02 D

C
1.25 D

D
None of these

Solution
Question 9
1 / -0

PCI_x F_{5 - x} shows non-polar behaviour when x is

A
0, 5

B
0

C
2, 1,4

D
0, 4, 1

Solution

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 PCl₅case chlorine's electronegativity cancels out each other.
In case of PCl₃F₂, 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 PF₃Cl₂ 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 PF₃Cl₂ is polar.
Question 10
1 / -0

Which of the following bonds is the weakest?

A
Coordinate bond

B
Hydrogen bond

C
van der Waals’ forces

D
Covalent bond

Solution

van der Waals` force is the weakest force of attraction and covalent bond is the strongest. Correct order is
Question 11
1 / -0

Which of the following would have a permanent dipole?

A
BF₃

B
SiF₄

C
SF₄

D
XeF₄

Solution

(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