MCQ Questions for Class 11 Medical Chemistry Chemical Bonding And Molecular Structure Quiz 1

The strength of sigma bonds formed by axial overlap of

$s-$ or

$p-$ orbitals of

$2nd$ shell of participating atom decreases as:

0%
$s-s>p-s>p-p$
0%
$s-s>p-p>s-p$
0%
$p-s>s-s>p-p$
0%
$p-p>s-p>s-s$

Which one of the of the following molecules is expected to have zero dipole moment?

0%
$H_2O$
0%
$CO_2$
0%
$SO_2$
0%
$CaF_2$

The number of P-O-P and P-O-H bonds present respectively in pyrophosphoric acid molecule are_____

0%
1,2
0%
2,2
0%
1,4
0%
1,8

Which formulae does not correctly represents the bonding capacity of the atom involved?

The number of electron pairs in

$Xe{F}_{4}$ at the corners of the square are _______.

0%
2
0%
3
0%
4
0%
6

Explanation

From its structure it can be seen that, number of electron pairs in

$XeF_4$ at the corners of the square are four

What is the electronic configuration of elements of

$III$ rd group

0%
$1{ s }^{ 2 },2{ s }^{ 2 }2p{ s }^{ 3 }$
0%
$1{ s }^{ 2 },2{ s }^{ 2 }2{ p }^{ 6 },3{ s }^{ 2 }3{ p }^{ 1 }$
0%
$1{ s }^{ 2 },2{ s }^{ 2 }2{ p }^{ 6 }$
0%
$1{ s }^{ 2 },2{ s }^{ 2 }2{ p }^{ 6 },3{ s }^{ 1 }\quad$

Explanation

$1{ s }^{ 2 },2{ s }^{ 2 }2{ p }^{ 6 },3{ s }^{ 2 }3{ p }^{ 1 }$
As it is p block element therefore the group is

$12+1=13$ (III A group)

For which of the following molecule significant

$\mu \neq 0?$

0%
Only $(c)$
0%
$(c)\: and\:(d)$
0%
Only $(a)$
0%
$(a)\: and\:(b)$

Explanation

For p-dichlorobenzene and p-dicyanobenzene, the dipole moments of individual bonds cancel each other as they are equal in magnitude and opposite in direction. Hence, the resultant dipole moment of the molecules is zero. For p-hydroquinone and p-benzenedithiol, the $O-H$ and $S-H$ bond dipoles in these molecules do not cancel each other as they are not in opposite directions due to existence in different conformations. Hence, the resultant dipole moment of the molecules is non zero.

Identify the pair in which the geometry of the species is T-shape and square pyramidal, respectively.

0%
$ClF_3$ and $IO^-_4$
0%
$ICl^-_2$ and $ICl_5$
0%
$IO^-_3$ and $IO_2F^-_2$
0%
$XeOF_2$ and $XeOF_4$

Boron cannot form which one of the following anions?

0%
$\mathrm{B}\mathrm{F}_{6}^{3-}$
0%
$\mathrm{B}\mathrm{H}_{4}^{-}$
0%
$\mathrm{B}(\mathrm{O}\mathrm{H})_{4}^{-}$
0%
$\mathrm{B}\mathrm{O}_{2}^{-}$

The number and type of bonds in

$C_{2}^{2-}$ ion in

$CaC_2$ are :

0%
one $\sigma$ bond and one $\pi$ -bond
0%
one $\sigma$ bond and two $\pi$ -bonds
0%
two $\sigma$ bonds and two $\pi$ -bonds
0%
two $\sigma$ bonds and one $\pi$ - bond

Explanation

$C_2^{2-}$ ion

$\longrightarrow$

$[C\equiv C]^{2-}$

Dicarbide ion

$C_2^{2-}$ has 1 sigma and 2 pi bonds. There are two

$\pi$ bonds and one

$\sigma$ bond in a triple bond.

Hence, the correct option is

$(B)$ .

Which of the following molecules has two sigma

$(\sigma)$ and two pi

$(\pi)$ bonds?

0%
$C_2H_4$
0%
$N_2F_2$
0%
$C_2H_2Cl_2$
0%
$HCN$

Explanation

The structure of HCN is

$H-C\equiv N$ . It has

$2 \pi$ and

$2 \sigma$ bonds.

Total number of lone pair of electrons in

$I_3{^-}$ ion is :

0%
$9$
0%
$12$
0%
$3$
0%
$6$

Among the following, the molecule with the highest dipole moment is:

0%
$\mathrm{C}\mathrm{H}_3 {Cl}$
0%
$\mathrm{C}\mathrm{H}{}_{2}\mathrm{C}l_{2}$
0%
$\mathrm{C}\mathrm{H}\mathrm{C}l_{3}$
0%
$\mathrm{C}\mathrm{C}l_{4}$

Explanation

$CCl_4 < CHCl_3 < CH_2Cl_2 <CH_3Cl$

$CCl_4$ dipole moment is 0 and The dipole moment of methyl chloride

$CH_3Cl$ is maximum. It is

$1.86$ D.

Which of the following pairs of ions are isoelectronic and isostructural?

0%
$SO_3^{2-}, NO_3^-$
0%
$ClO_3^-, CO_3^{2-}$
0%
$CO_3^{2-}, NO_3 {^-}$
0%
$ClO_3 {^-}, SO_3^{2-}$

Explanation

Hint: Those species which have the same number of electrons and identical shapes are called isoelectronic and isostructural species.

Correct Answer: Option C and D

Explanation:

Compound	Number of electrons	Hybridization	Shape	Structure
$SO_3^{2-}$	$16+2+24=42$	$sp^3$	Tetrahedral
$NO_3^-$	$7+24+1=32$	$sp^2$	Trigonal planar
$ClO_3^{-}$	$17+1+24=42$	$sp^3$	Tetrahedral
$CO_3^{2-}$	$6+24+2=32$	$sp^2$	Trigonal planner

Final Answer:

$NO_3^-$ and $CO_3^{2-}$ are isoelectronic and isostructural.

$SO_3^{2-}$ and $ClO_3^{-}$ are isoelectronic and isostructural.

$4d,5p,5f$ and

$6p$ orbitals are arranged in the order of decreasing energy.The correct option is:

0%
$5f>6p>5p>4d$
0%
$6p>5f>5p>4d$
0%
$6p>5f>4d>5p$
0%
$5f>6p>4d>5p$

Explanation

$(n+1)$ values for ,

$4d=4+2=6$

$5p=5+1=6$

$5f=5+3=8$

$6p=6+1=7$

$\therefore$ Correct order of energy would be

$5f>6p>5p>4d$

Which one of the following pairs of species have this same bond order?

0%
$N_{2}, {O}_{2}^{-}$
0%
$CO, NO$
0%
$O_{2}, NO^{+}$
0%
$CN^{-}, CO$

Explanation

$\displaystyle CN^{-}, CO$ are isoelectronic species (contains same number of electrons). They have same bond order.

0%
Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
0%
Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
0%
Assertion is correct but Reason is incorrect
0%
Both Assertion and Reason are incorrect

Explanation

Chlorine reacts more rapidly with

$H_2$ to form HCl which having an ionic bond. An ionic bond is stronger than a covalent bond.

MnO is?

0%
Ferromagnetic
0%
Antiferromagnetic
0%
Ferrimagnetic
0%
Dimagnetic

Which of the following phenomena will occur when two atoms of the elements having same spin of electron approach for bonding?

0%
Orbital overlap will not occur
0%
Bonding will not occur
0%
Both $A$ and $B$ are correct
0%
None of the above

Explanation

When two atoms of the elements having the same spin of electron approach for bonding, the orbital overlap will not occur and bonding will not occur. Hence, Both

$(A)$ and

$(B)$ are correct.
However, if two atoms of the elements having opposite spin of electron approach for bonding, the orbital overlap will occur and bonding will not occur.

Covalency of carbon in carbon dioxide is:

0%
$2$
0%
$4$
0%
$1$
0%
$0$

Explanation

$O=C=O$ , each oxygen shares 2 electron with carbon which makes the covalency 4

Molecule which contains only sigma bonds in it is:

0%
Pentene
0%
Pentane
0%
Pentadiene
0%
Pentyne

Explanation

The molecules

$A, C & D$ are alkene, alkyne and alkadiene. They contain both

$\sigma$ and

$\pi$ bonds. Alkanes undergo

$sp^3$ hybrid orbitals and do not contain any

$\pi$ bonds. They contain only

$\sigma$ bonds.

Maximum covalency of Sulphur is :

0%
$2$
0%
$4$
0%
$6$
0%
$8$

In the hydrocarbon,

$HC \equiv C-H$ , the covalency of carbon is :

0%
one
0%
two
0%
three
0%
four

Some atoms attain their inert gas configuration by sharing of electrons. This method of attaining inert gas configuration is known as :

0%
covalency
0%
electrovalency
0%
stabilisation
0%
inertness

The valency of an atom is equal to its combining capacity.

0%
True
0%
False

Explanation

If an element has some valency that is, for example,

$N - 1s^{2}2s^{2}2p^{3}$ here it has the combining the capacity of 3 that is it can share 3 electrons or accept three electrons. Here even valency is nothing but 3. Valency is defined as combining the power of the element with other elements.

Which of the following species has incomplete octet?

0%
$SiF_4$
0%
${ N }^{ 3- }$
0%
$Pbr5$
0%
${B}^{3-}$

Explanation

$B^{3-} - 1s^22s^22p^4$
incomplete octet

The number of lone pairs available on the central atom of sulphur tetrafluoride is :

0%
$0$
0%
$1$
0%
$2$
0%
$3$

Explanation

$\mathrm SF_{4}: sp^{3}d$

$1$ Lone pair of electrons.

In Lewis dot symbols dots indicates the __________.

0%
electrons
0%
neutrons
0%
protons
0%
quarks

The electro valency theory explains that atoms are held together by an___________that resulted due to transfer or sharing of electrons.

0%
repulsive forces
0%
attractive forces
0%
binding forces
0%
none of these

What is the covalency of

${O}_{2}$ and

${N}_{2}$ molecules?

0%
0,0
0%
1,2
0%
2,3
0%
3,3

Which one of these is weakest ?

0%
ionic bond
0%
covalent bond
0%
metallic bond
0%
van der Waal forces

A triple bond may be best described as :

0%
two sigma bonds and one $\pi$ bond
0%
one sigma bond and two $\pi$ bonds
0%
two sigma bonds and two $\pi$ bonds
0%
three $\sigma$ bonds
0%
three $\pi$ bonds

Explanation

A triple bond can be considered as one sigma bond and two pi bonds. The head-on overlap between two

$p_{x}$ orbitals of two-atom forms the sigma bond. The lateral/ or sideway overlap between

$p_{y}$ and

$p_{z}$ orbitals forms two

$\pi$ bonds. So the correct option is B

1935855_492317_ans_87042495edcc4f81af4d7f3e7dbf212b.jfif

The number of electron pair shared between two atoms of same or different elements during its formation of molecules is known as :

0%
covalency
0%
tetravalecy
0%
bivalency
0%
trivalency

A chemical bond between two atoms is:

0%
The tunnel in an atom through which the other one can pass
0%
The energy of the individual atoms
0%
The link between them
0%
A third, connecting atom

What is Bond formation?

0%
always exothermic
0%
always endothermic
0%
neither exothermic nor endothermic
0%
Sometimes exothermic and sometimes endothermic

An _____ bond is a bond in which electrons are transferred.

0%
Ionic
0%
Covalent
0%
Double
0%
Triple

The number of sigma and

$\pi$ bonds in 1-butene-3yne are-

0%
$5$ sigma and $5$ pi
0%
$7$ sigma and $3$ pi
0%
$8$ sigma and $2$ pi
0%
$6$ sigma and $4$ pi

Covalency of nitrogen in ammonium ion is:

0%
$2$
0%
$3$
0%
$4$
0%
$5$

Explanation

Hint: Covalency is equal to the number of bonds

In ammonium ion (

$\mathrm{NH_{4}^{+}}$ ), the nitrogen atom is bonded to

$4$ hydrogen atoms. Three hydrogens are covalently

bonded to nitrogen atom whereas the fourth hydrogen is bonded through a coordinate bond.

So total

$4$ bonds formed by the nitrogen atom. Therefore, the covalency of nitrogen atom is equal to

$4$ .

Final Answer: Option C

Molecule which contains only bonded pairs of electrons on the central atom is:

0%
$H_{2}O$
0%
$NH_{3}$
0%
$BeCl_{2}$
0%
$BF_{3}$

Explanation

$Be$ has

$2$ electrons in the valence shell (it belongs to group

$2$ of the periodic table).

Now both the electrons are involved in bond formation with both the

$Cl$ atoms. It comprises only bonded pair of electrons.

So, there are no lone pairs in the

$Be$ atom.

Hence, option C is correct.

Number of bonded electrons in ethane molecule are:

0%
$7$
0%
$12$
0%
$10$
0%
$14$

Explanation

Ethane consists of

$6\:C-H$ bonds and

$1\: C-C$ bond. Total number of bonds is

$7$ . Each bond is made up of two electrons. Thus, total bonded electrons are

$7\times2$ =

$14$ .

In which of the following molecule, the central atom has three lone pairs of electrons?

0%
Ammonia
0%
Xenon difluoride
0%
Chlorine trifluoride
0%
Hydrogen sulphide

Explanation

Xenon difluoride is

$XeF_{2}$ .

$Xe$ is a noble gas. So, it has

$8$ electrons in the valence shell. Out of which,

$2$ are involved in formation of covalent bond with the

$2 \:F$ atoms. So,

$6$ electrons are left as unbonded. Therefore, lone pairs = half of

$6$ =

$3$ .

Molecule which contains

$4$ bonded pairs and

$2$ lone pairs of electrons on the central atom is:

0%
$XeF_{2}$
0%
$CO_{2}$
0%
$XeF_{4}$
0%
$SF_{6}$

Explanation

$Xe$ is a noble gas. It has

$8$ electrons in its valence shell. Now, it is bonded to

$4\: F$ atoms.

So,

$4$ of its electrons are involved in bonding.

Hence, bond pairs =

$4$ . Remaining

$4$ are unbonded electrons. So, lone pairs =

$4 / 2 = 2$ .

Chemical bond implies ___________.

0%
repulsion
0%
attraction
0%
attraction and repulsion balanced at a particular distance
0%
attraction and repulsion

$Cl+Cl\rightarrow Cl_{2}$ , this is an example for __________.

0%
Endothermic reaction
0%
Exothermic reaction
0%
Either exothermic or endothermic
0%
Neither exothermic nor endothermic

Explanation

$Cl^{\cdot} + Cl^{\cdot} \longrightarrow Cl : Cl$

As two Chlorine atoms come together their electrostatic energy decreases. According to the law of conservation of energy, this energy will be transformed into heat energy.
So,

$Cl + Cl \longrightarrow Cl_{2}$ is exothermic reaction.

Molecule having maximum number of covalent bonds is:

0%
$NH_{4}OH$
0%
$NH_{4}Cl$
0%
$CO(NH_{2})_{2}$
0%
$CH_{3}OH$

Explanation

Urea has maximum covalent bonds -

$8$ .

Maximum covalency of nitrogen is:

0%
$4$
0%
$5$
0%
$3$
0%
$6$

The number of lone pairs on chlorine atom in

$\mathrm{Cl}\mathrm{O}^{-},$

$\mathrm{Cl}\mathrm{O}^{-}_{2},\ \mathrm{Cl}\mathrm{O}^{-}_{3},\ \mathrm{C}\mathrm{l}\mathrm{O}^{-}_{4}$ ions are:

0%
$0, 1, 2, 3$
0%
$1, 2, 3, 4$
0%
$4, 3, 2, 1$
0%
$3, 2, 1, 0$

Explanation

Lone pairs are in the order: 3, 2, 1 and 0 respectively as shown in the figure

Hence, option

$D$ is correct..

According to VSEPR theory, the shape of the water molecule is :

0%
linear
0%
planar triangle
0%
angular
0%
octahedral

The covalency of central atom is maximum in:

0%
$HCN$
0%
$NH_{4}^+$
0%
$PCl_{5}$
0%
$H_{2}O$

Explanation

$\bf{Hint-}$ Covalency is the measure of the number of bonds formed by the central atom of a covalent compound.

$\bf{Explanation-}$

$\bullet$ Hydrogen cyanide consists of three elements but is a binary compound made up of hydrogen and cyanide molecules. A single bond connects the two groups.

$H-CN$

$\bullet$ Ammonium ion is formed when ammonia acts as a base and accepts a proton from any acidic source. The central atom is a nitrogen atom that is connected to three neutral hydrogen atoms and one proton thus its covalency is four.

$NH_{4}{}^{+}$

$\bullet$ Phosphorus pentachloride is formed from the reaction of chlorine gas and white phosphorus. Phosphorus is in its maximum oxidation state and is covalently bonded to five monovalent chlorine atoms. Thus the covalency is five.

$PCl_5$

$\bullet$ Water molecule is formed when a divalent oxygen atom combines with two hydrogen atoms to give a bent geometry. There are two covalent bonds that connect the three atoms together and therefore the covalency is two.

$H_2O$

$\bf{Conclusion-}$ Thus, maximum covalency is observed in the case of Phosphorus pentachloride which is five. Therefore, option

$C$ is correct.

Compound having maximum number of bonded pairs of electrons in its molecule is:

0%
Ethane
0%
Ammonia
0%
Sulphur hexafluoride
0%
Bromine Pentafluoride

Explanation

(a) Ethane has

$6 \:C-H$ bonds and

$1 \:C-C$ bond.
(b) Ammonia has

$3\: N-H$ bonds.
(c) Sulphur hexafluoride has

$6\: S-F$ bonds.
(d) Bromine pentafluoride has

$5\: Br-F$ bonds.

CBSE Questions for Class 11 Medical Chemistry Chemical Bonding And Molecular Structure Quiz 1 - MCQExams.com

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Practice Class 11 Medical Chemistry Quiz Questions and Answers

CBSE Questions for Class 11 Medical Chemistry Chemical Bonding And Molecular Structure Quiz 1 - MCQExams.com

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Practice Class 11 Medical Chemistry Quiz Questions and Answers

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