Objective Chemistry for Engineering and Medical Entrance Examinations

K Rama Rao

Chapter 4

Chemical Bonding And Molecular Structure - all with Video Answers

Educators

Chapter Questions

Problem 1

Which of the following molecules is adequately represented by a single Lewis structure?
(1) $\mathrm{O}_{3}$
(2) NOCl
(3) $\mathrm{SO}_{2}$
(4) $\mathrm{N}_{2} \mathrm{O}$

Hunza Gilgit

Hunza Gilgit

Numerade Educator

Problem 2

In $\mathrm{PO}_{4}^{3}$ the formal charge on each oxygen atom and the P-O bond order are respectively
(1) $-0.75,0.5$
(2) $-0.75,1.25$
(3) $-0.75,1.0$
$(4)-3,1.25$

Hunza Gilgit

Numerade Educator

Problem 3

The formal charges on the three atoms in $\mathrm{O}_{3}$ molecule are
(1) $0,0,0$
(2) $0,0,-1$
(3) $0,0,+1$
(4) $0,+1,-1$

Hunza Gilgit

Numerade Educator

Problem 4

The most likely arrangement of atoms in $\mathrm{S}_{2} \mathrm{Cl}_{2}$ is
(1) S-S-C]-Cl
(2) $\mathrm{S}-\mathrm{Cl}-\mathrm{S}-\mathrm{Cl}$
(3) S-CI-Cl-S
(4) $\mathrm{Cl}-\mathrm{S}-\mathrm{S}-\mathrm{Cl}$

Hunza Gilgit

Numerade Educator

Problem 5

The way of writing Lewis structure of the cyanate ion OCN - places one double bond between the carbon atom and the oxygen atom and another double bond between the carbon atom and nitrogen atom. What are the formal charges on the oxygen, carbon and nitrogen atoms, respectively for those structures?
(1) $0,0,1$
(2) $1,0,0$
(3) 111,1
(4) $2,1,0$

Mishal Gul

Numerade Educator

Problem 6

Which of the following is the correct and stable electron dot structure of $\mathrm{N}_{2} \mathrm{O}$ molecule?
(1) $\mathrm{N}=\mathrm{N}=\mathrm{O}$ :
(2) $\mathrm{N} \equiv \mathrm{N} \quad \mathrm{O}$
(3) $\mathrm{N}=\mathrm{N}=\mathrm{O}$ :
(4) $\mathrm{N}=\mathrm{N}=\mathrm{O}$

Hunza Gilgit

Numerade Educator

Problem 7

During the bond formation normally all the elements in their outermost shell acquire
(1) 2 electrons
(2) 4 electrons
(3) 8 electrons
(4) 10 electrons

Hunza Gilgit

Numerade Educator

Problem 8

Chemical bond formation takes place when
(1) Energy is absorbed
(2) Forces of attraction overcome forces of repulsion
(3) Forces of repulsion overcome forces of attraction
(4) Forces of attraction arc equal to forces of repulsion

Hunza Gilgit

Numerade Educator

Problem 9

All chemical bonds are the result of
(1) interaction of nuclei
(2) interaction of electrons
(3) difference in electronegativity
(4) interaction of electron and nuclei

Hunza Gilgit

Numerade Educator

Problem 10

Which of the following statements is wrong in the reaction of sodium and chlorine?
(1) Energy is released and ionic bond is formed.
(2) In sodium chloride crystal cach $\mathrm{Na}^{+}$ ion is surrounded by eight Cl- ions.
(3) Each unit cell of sodium chloride consists of $4 \mathrm{Na}^{+} \mathrm{Cl}^{-}$ ionic pairs.
(4) Sodium is oxidised and chlorine is reduced.

Hunza Gilgit

Numerade Educator

Problem 11

The false statement among the following is
(1) lonic reactions take place in solution state.
(2) When elements form compounds they become stable by decreasing the energy content.
(3) An electrovalent compound is made of electrically charged particles.
(4) Electrovalent compounds exhibit stereoisomerism.

Hunza Gilgit

Numerade Educator

Problem 12

Many ionic crystals dissolve in water because
(1) water is an amphiprotic solvent
(2) water is a high boiling liquid
(3) the process is accompanied by a positive heat of solution
(4) Water decreases the interionic attraction in the crystal lattice due to solvation

Hunza Gilgit

Numerade Educator

Problem 13

The atomic numbers of three elements $\Lambda, B$, and $C$ are $\mathrm{a}, \mathrm{a} \mid \mathrm{l}$ and $\mathrm{a}$ ? $2 . \mathrm{C}$ is an alkali metal. In compounds $\Lambda$ and $C$ the nature of bonding is
(1) Coordinate
(2) Covalent
(3) Ionic
(4) Metallic

Mishal Gul

Numerade Educator

Problem 14

The electronic configurations of four elements $L, P, Q$ and $\mathrm{R}$ are given below. $L=1 s^{2} 2 s^{2} 2 p^{4} ; Q=1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{5}$
$P=1 s^{2} 2 s^{2} 2 p^{6} 3 s^{1} ; R=1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2}$
The formula of ionic compounds that can be formed between these elements are
(1) $\mathrm{L}_{2} \mathrm{P}, \mathrm{RL}, \mathrm{PQ}, \mathrm{R}_{2} \mathrm{Q}$
(2) $\mathrm{LP}, \mathrm{RL}, \mathrm{PQ}, \mathrm{RQ}$
(3) $\mathrm{P}_{2} \mathrm{~L}, \mathrm{RL}, \mathrm{PQ}, \mathrm{RQ}_{2}$
(4) $\mathrm{LP}, \mathrm{R}_{2} \mathrm{~L}, \mathrm{P}_{2} \mathrm{Q}, \mathrm{RQ}$

Mishal Gul

Numerade Educator

Problem 15

Which among the following is expected to conduct electricity?
(1) Diamond
(2) Molten sulphur
(3) Molten $\mathrm{KCl}$
(4) Crystalline $\mathrm{NaC} 1$

Hunza Gilgit

Numerade Educator

Problem 16

The false statement among the following when ionic compounds get dissolved in water is
(1) They involve heat changes.
(2) Interionic attraction is reduced due to solvation.
(3) Ions show dipole-ion attraction with water molecule.
(4) The cations are hydrolysed.

Hunza Gilgit

Numerade Educator

Problem 17

Solid NaCl is a bad conductor of electricity because
(1) In solid $\mathrm{NaCl}$, there are no ions.
(2) Solid NaCl is covalent.
(3) In solid $\mathrm{NaCl}$, there is no movement of ions.
(4) In solid $\mathrm{NaCl}$, there are no electrons.

Hunza Gilgit

Numerade Educator

Problem 18

An atom with atomic number 20 is most likely to combine chemically with the atom whose atomic number is
(1) 11
(2) 16
(3) 18
(4) 10

Hunza Gilgit

Numerade Educator

Problem 19

Born-Haber cycle is used to determine
(1) lattice energy
(2) electron affinity
(3) tonisation energy
(4) any of these

Hunza Gilgit

Numerade Educator

Problem 20

According to Fajan, covalent character of a compound is more when there are
(1) small cations and large anion
(2) small cations and small anion
(3) large cations and large anion
(4) large cations and small anion

Hunza Gilgit

Numerade Educator

Problem 21

If $\mathrm{Na}^{-}$ ion is larger than $\mathrm{Mg}^{2+}$ ion and $\mathrm{S}^{2-}$ ion is larger than $\mathrm{Cl}^{-}$ ion, which of the following will be least soluble in water?
(1) $\mathrm{NaCl}$
(2) $\mathrm{Na}_{2} \mathrm{~S}$
(3) $\mathrm{MgCl}_{2}$
(4) $\mathrm{MgS}$

Hunza Gilgit

Numerade Educator

Problem 22

Among $\mathrm{LiCl}, \mathrm{BeCl}_{2}, \mathrm{BCl}_{3}$ and $\mathrm{CCl}_{4}$ the covalent bond character follows the order
(1) $\mathrm{LiCl}>\mathrm{BeCl}_{2}>\mathrm{BCl}_{3}>\mathrm{CCl}_{4}$
(2) $\mathrm{LiCl}<\mathrm{BcCl}_{2}<\mathrm{BCl}_{3}>\mathrm{CCl}_{4}$
(3) $\mathrm{LiCl}>\mathrm{BcCl}_{2}>\mathrm{CCl}_{4}>\mathrm{BCl}_{3}$
(4) $\mathrm{LiCl}<\mathrm{BcCl}_{2}<\mathrm{BCl}_{3}>\mathrm{CCl}_{4}$

Hunza Gilgit

Numerade Educator

Problem 23

Among $\mathrm{NaP}, \mathrm{NaCl}, \mathrm{NaBr}$ and $\mathrm{Nal}$, the $\mathrm{NaF}$ has highest melting point because
(1) It has maximum ionic character.
(2) It has minimum ionic character.
(3) It has associated molecules.
(4) It has least molecular weight.

Hunza Gilgit

Numerade Educator

Problem 24

Amongst $\mathrm{LiCl}, \mathrm{RbCl}, \mathrm{BcCl}_{2}$ and $\mathrm{MgCl}_{2}$ the
compounds with the greatest and least ionic character respectively arc
(1) $\mathrm{LiCl}$ and $\mathrm{RbC} 1$
(2) $\mathrm{RbCl}$ and $\mathrm{BeCl}_{2}$
(3) $\mathrm{RbC} 1$ and $\mathrm{MgCl}_{2}$
(4) $\mathrm{MgC}_{2}$ and $\mathrm{BeCl}_{2}$

Hunza Gilgit

Numerade Educator

Problem 25

The three-dimensional graph of lattice points which sets the pattern for the whole lattice is called
(1) unit cell
(2) crystal lattice
(3) simple latticc
(4) space lattice

Hunza Gilgit

Numerade Educator

Problem 26

Favourable conditions for ionic bond are
(1) low charge on ions, large cation and small anion
(2) high charge on ions, small cation and large anion
(3) high charge on ions, large cation and small anion
(4) low charge on ions, small cation and large anion

Hunza Gilgit

Numerade Educator

Problem 27

Coordination number of Na ion in $\mathrm{NaCl}$ is 6 and that of cacsium ion in CsCl is 8 . This is because
(1) IP of $\mathrm{Cs}$ is less than $\mathrm{Na}$
(2) Size of $\mathrm{Na}^{\prime}$ is less than $\mathrm{Cs}$
(3) Attraction of $\mathrm{Na}$ is higher than $\mathrm{Cs}^{\prime}$
(4) None

Hunza Gilgit

Numerade Educator

Problem 28

$\mathrm{LiCl}$ is soluble in organic solvents while $\mathrm{NaCl}$ is not because
(1) Lattice energy of $\mathrm{NaCl}$ is less than that of $\mathrm{LiCl}$
(2) Li- has higher value of hydration energy than $\mathrm{Na}^{-}$
(3) LiCl is more covalent than $\mathrm{NaCl}$
(4) Li- has lower value of hydration energy than $\mathrm{Na}^{-}$

Hunza Gilgit

Numerade Educator

Problem 29

Which set has the strongest tendency to form anions?
(1) $\mathrm{Ga}, \ln , \mathrm{Te}$
(2) $\mathrm{Na}, \mathrm{M} \mathrm{g}, \mathrm{As}$
(3) $\mathrm{N}, \mathrm{O}, \mathrm{F}$
(4) $\mathrm{V}, \mathrm{Cr}, \mathrm{Mn}$

Hunza Gilgit

Numerade Educator

Problem 30

The relation between the magnitudes of lattice energy of crystal and its formation energy is
(1) Lattice energy $>$ Formation energy
(2) Lattice energy= Formation energy
(3) Lattice energy < Formation energy
(4) None

Hunza Gilgit

Numerade Educator

Problem 31

Using the following data calculate the electron affinity of chlorine. Heat of formation of $\mathrm{NaCl}\left(\Delta H_{f} \mathrm{NaCl}\right)$
$=98 \mathrm{Kcal} \mathrm{mole}^{-1}$
Disseciation energy of $\mathrm{Cl}_{2}\left(\frac{1}{2} \mathrm{D}_{\mathrm{C} 1}\right)$
$=+29 \mathrm{kcal} \mathrm{molc}^{-1}$
Heat of sublimation of $\mathrm{Na}\left(\Delta H_{s} \mathrm{Na}\right)$ $=+26$ keal mole ${ }^{\prime}$
IP of $\mathrm{Na}=1118 \mathrm{kcal} \mathrm{molc}^{-1}$
Lattice energy $(\mathrm{U})$ of $\mathrm{NaCl}(\mathrm{s})$
$=-184$ kcal mole ${ }^{1}$
(1) $17.14 \mathrm{kcal}$ mole $^{-1}$
(2) $48 \mathrm{kcal} \mathrm{mole}^{-1}$
(3) $87 \mathrm{kcal} \mathrm{molc}^{-1}$
(4) None

Mishal Gul

Numerade Educator

Problem 32

Octet rule is not valid for the molecule
(1) $\mathrm{CO}_{2}$
(2) $\mathrm{H}_{2} \mathrm{O}$
(3) $\mathrm{O}_{2}$
(4) CO

Hunza Gilgit

Numerade Educator

Problem 33

Regarding covalency which of the following statements is wrong?
(1) In covalency, sharing of electrons takes place.
(2) Maximum covalency is restricted to $8 .$
(3) Covalency is the number of electron pairs shared by an atom.
(4) Covalency of an atom is equal to the number of electrons contributed by an atom in the formation of covalent bonds.

Hunza Gilgit

Numerade Educator

Problem 34

The nature of bonding in $\mathrm{CCl}_{4}$ and $\mathrm{CaH}_{2}$ is
(1) electrovalent in both $\mathrm{CCl}_{4}$ and $\mathrm{CaH}_{2}$
(2) covalent in $\mathrm{CCl}_{4}$ and electrovalent in $\mathrm{CaH}_{2}$
(3) electrovalent in $\mathrm{CCl}_{4}$ and covalent in $\mathrm{CaH}_{2}$
(4) covalent in both $\mathrm{CCl}_{4}$ and $\mathrm{CaH}_{2}$

Hunza Gilgit

Numerade Educator

Problem 35

$\mathrm{CCl}_{4}$ is insoluble in water because
(1) $\mathrm{CCl}_{4}$ is nonpolar and water is polar
(2) water is nonpolar and $\mathrm{CCl}_{4}$ is polar
(3) water and $\mathrm{CCl}_{4}$ arc both polar
(4) none

Hunza Gilgit

Numerade Educator

Problem 36

Which is not an exception to octet rule?
(1) $\mathrm{BF}_{3}$
(2) $\mathrm{SnCl}_{4}$
(3) $\mathrm{Bel}_{2}$
(4) $\mathrm{ClO}_{2}$

Hunza Gilgit

Numerade Educator

Problem 37

The compound with lowest melting point is
(1) $\mathrm{A} 1 \mathrm{~F}_{3}$
(2) $\mathrm{AlCl}_{3}$
(3) $\mathrm{A} 1 \mathrm{Br}_{3}$
(4) $\mathrm{AlI}_{3}$

Hunza Gilgit

Numerade Educator

Problem 38

A solid substance is soft, has low melting point and is poor conductor of electricity. The substance is most likely
(1) an ionic solid
(2) network solid
(3) a metallic solid
(4) a molecular solid

Hunza Gilgit

Numerade Educator

Problem 39

When a solution of silver nitrate is added to pure carbon tetrachloride
(1) A white curdy precipitate soluble in ammonia is obtained
(2) A curdy precipitate insoluble in ammonia is obtained.
(3) A pale yellow precipitate is obtained.
(4) No precipitate is obtained.

Hunza Gilgit

Numerade Educator

Problem 40

The electronic configuration of 4 elements $\mathrm{K}, \mathrm{L}, \mathrm{M}$ and $\mathrm{N}$ are $K=1 s^{2} 2 s^{2} 2 p^{1}$
$L=1 s^{2} 2 s^{2} 2 p^{6}$
$\mathrm{M}=1 \mathrm{~s}^{2} 2 \mathrm{~s}^{2} 2 \mathrm{p}^{4}$
$\mathrm{N}=1 \mathrm{~s}^{2} 2 \mathrm{~s}^{2} 2 \mathrm{p}^{3}$
The element that would form a diatomic molecule with double bond is
(1) $\mathrm{K}$ $\begin{array}{lll}\text { (2) L } & \text { (3) } \mathrm{M} & \text { (4) } \mathrm{N}\end{array}$

Hunza Gilgit

Numerade Educator

Problem 41

The central atom in a molecule has three bond pairs and one lone pair of electrons. The shape of the molecule is
(1) Triangular
(2) Pyramidal
(3) Linear
(4) Tetrahedral

Hunza Gilgit

Numerade Educator

Problem 42

Which of the following molecules docs not have a linear arrangement of atoms?
(1) $\mathrm{C}_{2} \mathrm{II}_{2}$
(2) $\mathrm{II}_{2} \mathrm{O}$
(3) $\mathrm{BcCl}_{2}$
(4) $\mathrm{CO}_{2}$

Hunza Gilgit

Numerade Educator

Problem 43

Two lone pairs of electrons and two bond pairs are present in
(1) $\mathrm{NH}_{3}$
(2) BF $_{3}$
(3) $\mathrm{CO}_{3}^{2}$
(4) $\mathrm{H}_{2} \mathrm{O}$

Hunza Gilgit

Numerade Educator

Problem 44

$\mathrm{BCl}_{3}$ is a planar molecule, whercas $\mathrm{NCl}_{3}$ is pyramidal because
(1) $\mathrm{BCl}_{3}$ has no lonc pair of electrons but $\mathrm{NCl}_{3}$ has a lone pair of clectrons.
(2) B-Cl bond is more polar than N-Cl bond.
(3) Nitrogen atom is smaller than boron atom.
(4) N-Cl bond is more covalcnt than B-Cl bond.

Hunza Gilgit

Numerade Educator

Problem 45

More the number of lone pairs of electrons on the central atom
(1) greater is the contraction in the angle between bond pairs
(2) the smaller is the contraction in the angle between BPs
(3) no effect on bond angle
(4) all

Hunza Gilgit

Numerade Educator

Problem 46

The II-O-II bond angle in $\mathrm{II}_{2} \mathrm{O}$ is $104.5^{\circ}$ and not $109^{\circ} 28^{\prime}$ because of
(1) high electronegativity of oxygen
(2) bond pair-bond pair repulsion
(3) Lonc pair-lone pair repulsion
(4) Lonc pair-bond pair repulsion

Hunza Gilgit

Numerade Educator

Problem 47

The lone pair of electrons in a molecule spread out
(1) more than the bond pair electrons
(2) less than the bond pair electrons
(3) as much as the bond pair electrons
(4) only when they are present in oxygen atoms

Hunza Gilgit

Numerade Educator

Problem 48

The decrease in bond angle to $106^{\circ} 45^{-}$ from the tetrahedral angle in $\mathrm{NII}_{3}$ is because of
(1) bond pair-bond pair repulsion
(2) lone pair-lone pair repulsion
(3) bond pair-lone pair repulsion
(4) none

Hunza Gilgit

Numerade Educator

Problem 49

The geometrical arrangement and shape of $\mathrm{I}_{3}$ are respectively
(1) trigonal bipyramidal geometry, linear shape
(2) hexagonal geometry, T-shape
(3) triangular planar geometry, pyramidal shape
(4) tetrahedral geometry, pyramidal shape

Hunza Gilgit

Numerade Educator

Problem 50

The bond angles of $\mathrm{N} 1 \mathrm{I}_{3}, \mathrm{NlI}_{4}$ and $\mathrm{NII}_{2}$ are in the order
(1) $\mathrm{NII}_{2}^{-}>\mathrm{NII}_{3}>\mathrm{NII}_{4}^{+}$
(2) $\mathrm{NII}_{4}^{+}>\mathrm{NII}_{3}>\mathrm{NII}_{2}^{-}$
(3) $\mathrm{NII}_{3}>\mathrm{NII}_{2}>\mathrm{NII}_{4}^{-}$
(4) $\mathrm{NII}_{3}>\mathrm{NII}_{4}^{+}>\mathrm{NII}_{2}^{-}$

Hunza Gilgit

Numerade Educator

Problem 51

The angle between the overlapping of one s-orbital and onc $\mathrm{p}$ -orbital is
(1) $180^{\circ}$
(2) $120^{\circ}$
(3) $109^{\circ} 28^{\prime}$
(4) $120^{\circ} 50^{\prime}$

Hunza Gilgit

Numerade Educator

Problem 52

A covalent bond is formed between the atoms by the overlapping of orbitals containing
(1) a single electron
(2) paired electron
(3) single electrons with parallel spin
(4) single electron with opposite spin

Hunza Gilgit

Numerade Educator

Problem 53

How many $\sigma$ and $\pi$ bonds are there in the molecule of tetracyanoethylene $(\mathrm{CN})_{2} \mathrm{C}=\mathrm{C}(\mathrm{CN})_{2} ?$
(1) Nine $\sigma$ and nine $\pi$
(2) Five $\sigma$ and nine $\pi$
(3) Nine $\sigma$ and seven $\pi$
(4) Five $\sigma$ and eight $\pi$

Hunza Gilgit

Numerade Educator

Problem 54

Which statement among the following is corrcct?
(1) $\pi$ -bond always cxist with $\sigma$ -bond
(2) $\pi$ -bond can exist indcpendently
(3) $\sigma$ -bond is weaker than $\pi$ -bond
(4) $\pi$ -bond is less reactive than $\sigma$ -bond

Hunza Gilgit

Numerade Educator

Problem 55

Which is not characteristic of a $\pi$ bond?
(1) A $\pi$ -bond is formed when a sigma bond is already formed.
(2) $\pi$ -bonds are formed by hybrid orbitals.
(3) $\pi$ -bonds may be formed by the overlapping of atomic orbitals.
(4) $\pi$ -bond results from lateral overlap of atomic orbitals.

Hunza Gilgit

Numerade Educator

Problem 56

Which p-orbital overlapping would give the strongest bond?

Hunza Gilgit

Numerade Educator

Problem 57

$\pi$ -bond
(1) shortens the bond length
(2) increases the bond length
(3) distorts the geometry of the molecule
(4) none

Hunza Gilgit

Numerade Educator

Problem 58

According to valence bond theory bond angle in water should be $90^{\circ} .$ But experimental value is $104.5^{\circ}$. This is due to
(1) repulsion between positively charged hydrogen atoms
(2) the presence of lone pair of electrons in oxygen
(3) repulsion between two bonds is very high
(4) None

Hunza Gilgit

Numerade Educator

Problem 59

The number of bonds present and the number of unpaired electrons according to valence bond theory in $\mathrm{O}_{2}$ are
(1) 2,2
(2) 2,0
(3) 3,0
(4) 0,2

Hunza Gilgit

Numerade Educator

Problem 60

Which of the following pairs of orbitals conform a pi bond?
(1) $\mathrm{p}_{\mathrm{y}}-\mathrm{p}_{y}$
(2) $\mathrm{p}_{y}-\mathrm{p}_{t}$
(3) $\mathrm{s}-\mathrm{p}_{\gamma}$
(4) $\mathrm{s}-\mathrm{s}$

Hunza Gilgit

Numerade Educator

Problem 61

Valence bond theory of Pauling and Slater accounts for $\ldots \ldots \ldots$ characteristics of covalent bond.
(1) strength
(2) directional
(3) both
(4) none of these

Hunza Gilgit

Numerade Educator

Problem 62

Which orbital is used by oxygen atom to form a sigma bond with other oxygen atom in $\mathrm{O}_{2}$ molecule?
(1) sp hybrid orbital
(2) $\mathrm{sp}^{2}$ hybrid orbital
(3) $\mathrm{sp}^{3}$ hybrid orbital
(4) pure p-orbital

Hunza Gilgit

Numerade Educator

Problem 63

Jodine monochloride molecule is formed by the overlap of
(1) s-s orbitals
(2) s-p orbitals
(3) p-d orbitals
(4) $\mathrm{p}-\mathrm{p}$ orbitals

Hunza Gilgit

Numerade Educator

Problem 64

Which of the following is not characteristic of a covalent bonding?
(1) s-orbital never participates in $\pi$ bonding
(2) it is effective only at small internuclear distances
(3) it is directional
(4) it is weaker than Van der Waal's bonding

Hunza Gilgit

Numerade Educator

Problem 65

Which of the following about covalent bond is false?
(1) energy is required to break a covalent bond
(2) covalent bonds involve overlap of orbitals
(3) covalent bonds are generally stronger than the ionic bonds
(4) covalent bonds are not formed by small atoms

Hunza Gilgit

Numerade Educator

Problem 66

Which has the planar structure?
(1) $\mathrm{NH}_{4}{ }^{\prime}$
(2) $\mathrm{SCl}_{4}$
(3) $\mathrm{XeF}_{4}$
(4) $\mathrm{BF}_{4}$

Hunza Gilgit

Numerade Educator

Problem 67

The molecule/ion which is not planar is
(1) $\mathrm{BF}_{3}$
(2) $\mathrm{NO}_{3}$
(3) $\mathrm{CO}_{3}^{2}$
(4) $\mathrm{NF}_{3}$

Hunza Gilgit

Numerade Educator

Problem 68

Which does not use $s p^{3}$ hybrid orbitals in its bonding?
(1) $\mathrm{BF}_{3}$
(2) $\mathrm{H}_{3} \mathrm{O}^{\prime}$
(3) $\mathrm{NH}_{4}$
(4) $\mathrm{NF}_{3}$

Hunza Gilgit

Numerade Educator

Problem 69

$\mathrm{O} \mathrm{F}_{2}$ is
(1) Lincar molccule
(2) Tetrahcdral moleculc
(3) Angular molecule
(4) Nonc

Hunza Gilgit

Numerade Educator

Problem 70

The molecule which is not linear is
(1) $\mathrm{CO}_{2}$
(2) $\mathrm{BeCl}_{2}$
(3) $\mathrm{Cl}_{2} \mathrm{O}$
(4) $\mathrm{IIgCl}_{2}$

Hunza Gilgit

Numerade Educator

Problem 71

Which has the lowest bond angle?
(1) $\mathrm{BeF}_{2}$
(2) $\mathrm{H}_{2} \mathrm{O}$
(3) $\mathrm{NH}_{3}$
(4) $\mathrm{CH}_{4}$

Hunza Gilgit

Numerade Educator

Problem 72

The type of hybridisation present in $\mathrm{SO}_{2}$ and $\mathrm{SO}_{3}$ is respectively
(1) $\mathrm{sp}, \mathrm{sp}^{2}$
(2) $\mathrm{sp}^{2}, \mathrm{sp}^{2}$
(3) $\mathrm{sp}^{2}, \mathrm{sp}^{3}$
(4) $\mathrm{sp}, \mathrm{sp}^{3}$

Hunza Gilgit

Numerade Educator

Problem 73

Which statement is wrong?
(1) IIybridisation is the mixing of atomic orbitals prior to thcir combining into molecular orbitals.
(2) sp $^{2}$ hybrid orbitals are formed from two $\mathrm{p}$ - and one s-atomic orbitals.
(3) sp $^{3} \mathrm{~d}$ hybrid orbitals are all at $90^{\circ}$ to one another.
(4) $\mathrm{sp}^{3} \mathrm{~d}^{2}$ hybrid orbitals are directed towards the corners of the regular octahedron.

Hunza Gilgit

Numerade Educator

Problem 74

$\mathrm{PCH}_{5}$ exists but $\mathrm{NCl}_{5}$ does not exist because
(1) Nitrogen has no vacant $2 \mathrm{~d}$ -orbitals.
(2) NCls is unstable.
(3) Nitrogen atom is much smaller than p.
(4) Nitrogen is highly inert.

Hunza Gilgit

Numerade Educator

Problem 75

The shape of $\mathrm{NO}_{3}^{-}$ is planar. It is formed by the overlapping of oxygen orbitals with which orbitals of nitrogen are
(1) sp $^{3}$ hybridised
(2) sp $^{2}$ hybridised
(3) sp hybridiscd
(4) 3 purc p-orbitals

Hunza Gilgit

Numerade Educator

Problem 76

Which hybridisation results in non-planar orbitals?
(1) sp
(2) $\mathrm{sp}^{2}$
(3) $\mathrm{sp}^{3}$
(4) $\mathrm{dsp}^{2}$

Hunza Gilgit

Numerade Educator

Problem 77

The hybridisation of carbon in diamond, graphitc and acctylene is
(1) $\mathrm{sp}^{3}, \mathrm{sp}^{2}$, sp
(2) $\mathrm{sp}^{3}, \mathrm{sp}, \mathrm{sp}^{2}$
(3) $\mathrm{sp}^{2}, \mathrm{sp}^{3}, \mathrm{sp}$
(4) $\mathrm{sp}, \mathrm{sp}^{2}, \mathrm{sp}^{3}$

Hunza Gilgit

Numerade Educator

Problem 78

$\mathrm{CO}_{2}$ has the same geomctry as
$(\Lambda) \mathrm{IIgCl}_{2}$
(B) $\mathrm{NO}_{2}$
(C.) $\mathrm{SnCl}_{4}$
(D) $\mathrm{C}_{2} \mathrm{II}_{2}$
(1) A and $C$
(2) $\mathrm{B}$ and $\mathrm{D}$
(3) $\mathrm{A}$ and $\mathrm{D}$
(4) $\mathrm{C}$ and $\mathrm{D}$

Hunza Gilgit

Numerade Educator

Problem 79

The pair having similar geometry
(1) $\mathrm{BF}_{3}, \mathrm{NH}_{3}$
(2) $\mathrm{BF}_{3}, \mathrm{~A} \mathrm{KCl}_{3}$
(3) $\mathrm{BeF}_{2}, \mathrm{H}_{2} \mathrm{O}$
(4) $\mathrm{BCl}_{3}, \mathrm{PCH}_{3}$

Hunza Gilgit

Numerade Educator

Problem 80

$\mathrm{CO}_{2}$ is isostructural with
(1) $\mathrm{SnCl}_{2}$
(2) $\mathrm{IgCl}_{2}$
(3) $\mathrm{II}_{3} \mathrm{O}^{+}$
(4) $\mathrm{SCl}_{2}$

Hunza Gilgit

Numerade Educator

Problem 81

Which has triangular planar shape?
(1) $\mathrm{CH}_{3}^{-}$
(2) $\mathrm{ClO}_{2}^{-}$
(3) $\mathrm{H}_{3} \mathrm{O}^{+}$
(4) $\mathrm{ClO}_{3}^{-}$

Hunza Gilgit

Numerade Educator

Problem 82

Which of the following pairs arc nonlincar?
(1) $\mathrm{NH}_{3}, \mathrm{CO}_{2}$
(2) $\mathrm{NH}_{3}, \mathrm{H}_{2} \mathrm{O}$
(3) $\mathrm{CO}_{2}, \mathrm{BeCl}_{2}$
(4) $\mathrm{BeCl}_{2}, \mathrm{NH}_{3}$

Hunza Gilgit

Numerade Educator

Problem 83

Which of the following statement is false?
(1) Octahedral molccular shape exists in sp $^{3} \mathrm{~d}^{2}$ hybridisation.
(2) $\mathrm{XcF}_{2}$ involves $\$ \mathrm{p}^{3} \mathrm{~d}$ hybridisation.
(3) The repulsion among four hybrid orbitals is smallest if they point to the corners of a square.
(4) IIybridisation can take place only between orbitals of roughly the same energy.

Hunza Gilgit

Numerade Educator

Problem 84

A triatomic molecule must be either linear with a bond angle of $180^{\circ}$ or else
(1) Pyramidal
(2) Tetrahedral
(3) Bent
(4) L-shaped

Hunza Gilgit

Numerade Educator

Problem 85

Odd number regarding the shape of the following is
(1) $\mathrm{BCl}_{3}$
(2) $\mathrm{PCl}_{3}$
(3) $\mathrm{NT}_{3}$
(4) $\mathrm{II}_{3} \mathrm{O}^{-}$

Hunza Gilgit

Numerade Educator

Problem 86

Increasing order of the size of various hybrid orbitals is
(1) $s p>s p^{2}>8 p^{3}$
(2) $s p^{3}>s p^{2}>s p$
(3) $\mathrm{sp}^{2}>\mathrm{sp}>8 \mathrm{p}^{3}$
(4) $5 p>8 p^{3}>s p^{2}$

Hunza Gilgit

Numerade Educator

Problem 87

Which one of the following is not a consequence of hybridisation?
(1) effective overlapping of orbitals
(2) minimised repulsion between orbital electrons
(3) stronger bonds
(4) enhanced reactivity of the molecule

Hunza Gilgit

Numerade Educator

Problem 88

$\mathrm{PCl}_{5}$ in the solid state cxists as $\mathrm{PCl}_{4}^{+}$ and $\mathrm{PCl}_{6}^{-}$ because
(1) Solid $\mathrm{PCl}_{5}$ is a conduetor.
(2) $\mathrm{PCl}_{4}$ and $\mathrm{PCl}_{6}$ have stable symmetrical structures unlike $\mathrm{PCl}_{5}$ that has asymmetrical strueture.
(3) lon pairs are more stable than neutral molecules.
(4) Phosphorous belongs to $\mathrm{V}$ group in the periodic table.

Hunza Gilgit

Numerade Educator

Problem 89

Regarding hybridisation which is incorrect?
(1) $\mathrm{BF}_{3}, \mathrm{C}_{2} \mathrm{H}_{4}, \mathrm{C}_{6} \mathrm{H}_{6}$ involves sp $^{2}$ hybridisation.
(2) $\mathrm{BeF}_{2}, \mathrm{C}_{2} \mathrm{H}_{2}, \mathrm{CO}_{2}$ involves sp hybridisation.
(3) $\mathrm{NH}_{3}, \mathrm{H}_{2} \mathrm{O}, \mathrm{CCl}_{4}$ involves sp $^{3}$ hybridisation.
(4) $\mathrm{CH}_{4}, \mathrm{C}_{2} \mathrm{H}_{4}, \mathrm{C}_{2} \mathrm{H}_{2}$ involves $\mathrm{sp}^{2}$ hyoridisation.

Hunza Gilgit

Numerade Educator

Problem 90

The $\% \mathrm{p}$ character in hybrid orbitals of the central atom of watcr molecule is
(1) $25 \%$
(2) $75 \%$
(3) Less than $75 \%$
(4) More than $75 \%$

Hunza Gilgit

Numerade Educator

Problem 91

When two species A and B form an electron pair bond and A does not provide its electrons for bonding, the bond present between $\mathrm{A}$ and $\mathrm{B}$ must be
(1) ionie
(2) covalent
(3) dative
(4) hydrogen

Hunza Gilgit

Numerade Educator

Problem 92

Each of the following pairs of chemical species will combine. Which of the following combination is best explained by the coordinate covalcnt bond?
(1) $\mathrm{II}_{2} \stackrel{1}{I}_{2}$
(2) $\mathrm{Mg}$ ? $\mathrm{O}_{2}$
(3) $\mathrm{Cl} \perp \mathrm{Cl}$
(4) II $^{+} 1 \mathrm{II}_{2} \mathrm{O}$

Hunza Gilgit

Numerade Educator

Problem 93

$\mathrm{B} \mathrm{F}_{3}$ forms an adduct with $\mathrm{NH}_{3}$ because
(1) Nitrogen has high clectroncgativity.
(2) Boron has high clectroncgativity.
(3) Boron has an empty p-orbital and nitrogen has one lonc pair of clectrons.
(4) Boron has clectropositive character.

Hunza Gilgit

Numerade Educator

Problem 94

Proton plays an important role in .......bonding.
(1) electrovalent
(2) hydrogen
(3) covalent
(4) coordinate

Hunza Gilgit

Numerade Educator

Problem 95

Which of the following compounds contain all three types: ionic, covalent and dative bonds?
(1) $\mathrm{CuSO}_{4} \cdot 5 \mathrm{I}_{2} \mathrm{O}$
(2) Solid $\mathrm{N}_{2} \mathrm{O}_{5}$
(3) $\left(\mathrm{NIL}_{4}\right)_{2} \mathrm{SO}_{4}$
(4) $\Lambda$ Il

Hunza Gilgit

Numerade Educator

Problem 96

The type of bond formed during the hydration of cation is
(1) ionic
(2) covalent
(3) electrostatic
(4) dative bond

Hunza Gilgit

Numerade Educator

Problem 97

The bond order of a molecule is given by
(1) Half the difference between number of bonding electrons and anti-bonding electrons.
(2) The difference between the number of bonding electrons and anti-bonding electrons.
(3) Twice the difference between the number of bonding electrons and anti-bonding electrons.
(4) The total number of bonding electrons.

Hunza Gilgit

Numerade Educator

Problem 98

Which of the following statement is correct?
(1) Non-bonding orbitals have the same energy as the bonding MOs.
(2) Anti-bonding MOs have higher energies than highest cnergy atomic orbitals from which they are formed.
(3) Bonding orbitals have higher energies than the anti-bonding MOs.
(4) $\boldsymbol{\Lambda l l}$ are correct.

Hunza Gilgit

Numerade Educator

Problem 99

Bond order in the MO theory depends on the number of bonding electrons and anti-bonding electrons. The bond order
(1) always has an integer value
(2) can have only fractional valuc
(3) is always equal to onc
(4) can be zero, integral or fractional

Hunza Gilgit

Numerade Educator

Problem 100

Given $\mathrm{H}_{2}, \mathrm{H}_{2}$ and $\mathrm{He}_{2}$, the correct order of increasing bond energy is
(1) $\mathrm{H}_{2}<\mathrm{H}_{2}^{\prime}<\mathrm{He}_{2}$
(2) $\mathrm{He}_{2}^{\prime}<\mathrm{H}_{2}^{\prime}<\mathrm{H}_{2}$
(3) $\mathrm{H}_{2}^{\prime}<\mathrm{He}_{2}^{\prime}<\mathrm{H}_{2}$
(4) $\mathrm{H}_{2}<\mathrm{He}_{2}^{\prime}<\mathrm{H}_{2}$

Hunza Gilgit

Numerade Educator

Problem 101

Each one of the following molecule/ion is paramagnetic cxcept.
(1) $\mathrm{O}_{2}$
(2) $\mathrm{O}_{2}^{\prime}$
(3) $\mathrm{O}_{\frac{2}{2}}^{2}$
(4) $\mathrm{O}_{2}$

Hunza Gilgit

Numerade Educator

Problem 102

Which of the following molecules do not exist?
(1) $\mathrm{II}_{2}$
(2) $\mathrm{Bc}_{2}$
(3) $\mathrm{C}_{2}$
(4) $\mathrm{N}_{2}$

Hunza Gilgit

Numerade Educator

Problem 103

Which one of the following molecule has the shortest bond length?
(1) $\mathrm{C}_{2}$
(2) $\mathrm{O}_{2}$
(3) $\mathrm{F}_{2}$
(4) $\mathrm{N}_{2}$

Hunza Gilgit

Numerade Educator

Problem 104

Which of the following diatomic species do you expect to have the longest bond length?
(1) $\mathrm{N}_{2}$
(2) $\mathrm{O}_{2}$
(3) $\mathrm{O}_{2}$
(4) $\mathrm{N}_{2}^{\prime}$

Hunza Gilgit

Numerade Educator

Problem 105

In which of the following pairs, both the species have the same bond order?
(1) $\mathrm{N}_{2}, \mathrm{~N}_{2}^{21}$
(2) $\mathrm{O}_{2}, \mathrm{~F}_{2}$
(3) $\mathrm{C}_{2}, \mathrm{O}_{2}$
(4) $\mathrm{C}_{2}, \mathrm{~N}_{2}$

Hunza Gilgit

Numerade Educator

Problem 106

In which set both species are paramagnetic?
(1) $\mathrm{B}_{2}, \mathrm{O}_{2}$
(2) $\mathrm{N}_{2}, \mathrm{~T}_{2}$
(3) $\mathrm{Be}_{2}, \mathrm{O}_{2}$
(4) $\mathrm{N}_{2}, \mathrm{O}_{2}$

Hunza Gilgit

Numerade Educator

Problem 107

The bond order in $\mathrm{N}_{2}^{-}$ is same as in except
(1) $\mathrm{O}_{2}^{+}$
(2) $\mathrm{N}_{2}^{-}$
(3) $\mathrm{C}_{2}^{-}$
(4) $\mathrm{O}_{2}^{2-}$

Hunza Gilgit

Numerade Educator

Problem 108

Which of the following set have lowest bond order?
(1) $\mathrm{H}_{2}$ and $\mathrm{He}_{2}{ }^{\prime}$
(2) $\mathrm{H}_{2}$ and $\mathrm{He}_{2}{ }^{\prime}$
(3) $\mathrm{Li}_{2}$ and $\mathrm{H}_{2}$
(4) $\mathrm{H}_{2}$ and $\mathrm{B}_{2}$

Hunza Gilgit

Numerade Educator

Problem 109

The MO clectron configuration of peroxide ion $\left(O_{2}^{2}\right)$ is
(1) $\mathrm{KK}^{*}\left[\sigma 2 \mathrm{~s}^{2} \sigma^{*} 2 \mathrm{~s}^{2} \sigma 2 \mathrm{p}_{x}^{2} \pi 2 \mathrm{p}_{x}^{2} \pi 2 \mathrm{p}_{\mathrm{y}}^{2} \pi * 2 \mathrm{p}_{x}^{2} \pi+2 \mathrm{p}_{\mathrm{y}}^{2}\right]$
(2) $\mathrm{KK}^{*} \mid \sigma 2 \mathrm{~s}^{2} \sigma^{*} 2 \mathrm{~s}^{2} \sigma 2 \mathrm{p}_{z}^{2} \pi 2 \mathrm{p}_{\mathrm{x}}^{2} \pi 2 \mathrm{p}_{\mathrm{y}}^{2} \pi^{*} 2 \mathrm{p}_{\mathrm{x}}^{1} \pi^{*} 2 \mathrm{p}_{\mathrm{y}}^{1} \mathrm{l}$
(3) $\mathrm{KK}^{*}\left[\sigma 2 \mathrm{~s}^{2} \sigma^{*} 2 \mathrm{~s}^{2} \sigma 2 \mathrm{p}_{z}^{2} \pi 2 \mathrm{p}_{\mathrm{x}}^{2} \pi 2 \mathrm{p}_{y}^{2} \pi^{*} 2 \mathrm{p}_{\mathrm{x}}^{2} \pi^{*} 2 \mathrm{p}_{y}^{\prime}\right]$
(4) $\mathrm{KK}^{*} \mid \sigma 2 \mathrm{~s}^{2} \sigma^{*} 2 \mathrm{~s}^{2} \sigma 2 \mathrm{p}_{k}^{2} \pi 2 \mathrm{p}_{x}^{2} \pi 2 \mathrm{p}_{y}^{2} \pi * 2 \mathrm{p}_{\mathrm{x}}^{2} \mathrm{l}$

Kajal Gautam

Numerade Educator

Problem 110

Which of the following set bas bighest bond order?
(1) $\mathrm{N}_{2}, \mathrm{O}_{2}$
(2) $\mathrm{N}_{2}, \mathrm{O}_{2}^{21}$
(3) $\mathrm{O}_{2}^{2-}, \mathrm{O}_{2}^{2-}$
(4) $\mathrm{O}_{2}, \mathrm{C}_{2}$

Hunza Gilgit

Numerade Educator

Problem 111

A molecular orbital in a polyatomic molecule is
(1) monocentric
(2) bicentric
(3) polycentric
(4) none of these

Hunza Gilgit

Numerade Educator

Problem 112

Which of the following sets are isoelectronic?
(1) $\mathrm{N}_{2}, \mathrm{O}_{2}^{2}$
(2) $\mathrm{N}_{2}, \mathrm{O}_{2}^{21}$
(3) $\mathrm{N}_{2}^{-}, \mathrm{O}_{2}^{-}$
(4) $\mathrm{N}_{2}, \mathrm{O}_{2}^{-}$

Hunza Gilgit

Numerade Educator

Problem 113

The bond in peroxide ion and fluorine molecule is equal because
(1) these are isoclectronic
(2) their bond cnergies arc ncarly equal
(3) their bond lengths are nearly cqual
(4) all of these

Hunza Gilgit

Numerade Educator

Problem 114

Which statement of the following is false for isoelectronic species?
(1) They have same outer electronic configuration.
(2) Their bond orders are same.
(3) Their outer electronic configuration is different.
(4) Their bond energies are nearly same.

Hunza Gilgit

Numerade Educator

Problem 115

In the conversion of $\mathrm{N}_{2}$ to $\mathrm{N}_{2}^{+}$ ion the electron is removed from
(1) $\sigma$ orbital
(2) $\sigma^{*}$ orbital
(3) $\pi$ orbital
(4) $\pi^{*}$ orbital

Hunza Gilgit

Numerade Educator

Problem 116

In the conversion of $\mathrm{O}_{2}$ to superoxide ion, the electron is added to
(1) $\sigma$ -orbital
(2) $\sigma^{*}$ -orbital
(3) $\pi$ -orbital
(4) $\pi^{*}$ -orbital

Hunza Gilgit

Numerade Educator

Problem 117

In an anti-bonding MO the clectron density is minimum
(1) around one atom of the molecule
(2) between the nuclei
(3) at a point away from nuclci of the molecule
(4) at no place

Hunza Gilgit

Numerade Educator

Problem 118

The paramagnetism of $\mathrm{O}_{2}$ molecule is believed to be due to the presence of two electrons in
(1) bonding $\pi$ -orbitals with parallel spin
(2) antibonding $\pi$ -orbitals with parallcl spin
(3) antibonding $\pi$ -orbitals with opposite spin
(4) antibonding o-orbitals with parallel spin

Hunza Gilgit

Numerade Educator

Problem 119

Which of the following statements is not correct?
(1) $\mathrm{He}_{2}$ molecule cannot exist.
(2) $\mathrm{H}_{2}^{+}$ ion is less stable than $\mathrm{H}_{2}$ molecule.
(3) $\mathrm{N}_{3}$ ion is less stable than $\mathrm{N}_{2}$ molcculc.
(4) The $\mathrm{O}-\mathrm{O}$ bond length in $\mathrm{O}_{2}$ less than that in ion.

Hunza Gilgit

Numerade Educator

Problem 120

Which of the following statements is correct?
(1) The peroxide ion has a bond order of $1.5$ while the oxygen molecule has a bond order of 2 .
(2) The peroxide ion has a longer and weaker bond than the oxygen molecule.
(3) The peroxide ion as well as the $O_{2}$ molecule is paramagnetic.
(4) The bond length of peroxide ion is shorter than that of $\mathrm{O}_{2}$ molecule.

Hunza Gilgit

Numerade Educator

Problem 121

Which set of the following spccies has a bond order of $2.5 ?$
(1) $\mathrm{N}_{2}^{+}, \mathrm{NO}, \mathrm{O}_{2}^{+}$
(2) $\mathrm{O}_{2}^{-}, \mathrm{NO}, \mathrm{CN}^{-}$
(3) $\mathrm{N}_{2}{ }^{\prime}, \mathrm{CN}, \mathrm{O}_{2}^{+}$
(4) $\mathrm{CN}, \mathrm{N} 2, \mathrm{~N}_{2}$

Hunza Gilgit

Numerade Educator

Problem 122

Which of the following statements is correct?
(1) If bond order is zero or negative the molecule formed is unstable.
(2) If bond order is positive, the bond formed is stable.
(3) Bond dissociation energy is directly proportional to the bond order.
(4) All arc correct.

Hunza Gilgit

Numerade Educator

Problem 123

Which of the following statements is not correct for species $\mathrm{O}_{2}{ }^{1}, \mathrm{O}_{2}, \mathrm{O}_{2}$ and $\mathrm{O}_{2}^{2} ?$
(1) Bond order decreases in the order:
$\mathrm{O}_{2}^{+}>\mathrm{O}_{3}>\mathrm{O}_{2}^{-}>\mathrm{O}_{2}^{2-}$
(2) Bond length increascs in the order:
$\mathrm{O}_{2}^{+}<\mathrm{O}_{2}>\mathrm{O}_{2}^{-}>\mathrm{O}_{2}^{2-}$

Kajal Gautam

Numerade Educator

Problem 124

Only on the basis of bond order which of the following statements is not correct for species NO, NO, $\mathrm{NO}^{2}$, and NO?
(1) Bond order follows the order:
$\mathrm{NO}^{+}>\mathrm{NO}=\mathrm{NO}^{-}>\mathrm{NO}^{-}$
(2) Bond cnergy follows the order:
$\mathrm{NO}^{+}>\mathrm{NO}=\mathrm{NO}^{2+}>\mathrm{NO}^{-}$
(3) Bond length follows the order:
$\mathrm{NO}^{\prime}<\mathrm{NO}=\mathrm{NO}^{2 \prime}<\mathrm{NO}$
(4) Stability decreases in the order:
$\mathrm{NO}^{+}<\mathrm{NO}=\mathrm{NO}^{2+}<\mathrm{NO}^{-}$

Kajal Gautam

Numerade Educator

Problem 125

Which of the following statements is not correct?
(1) The bond order of $\mathrm{CN}^{\prime}, \mathrm{CN}$ and $\mathrm{CN}$ follows the order $\mathrm{CN}>\mathrm{CN}>\mathrm{CN}$.
(2) The species $\mathrm{H}_{2}^{-}, \mathrm{C}_{2}^{+}$ and $\mathrm{F}_{2}^{+}$ have a bond order of $1.5$ each.
(3) The species $\mathrm{H}_{2}^{-}, \mathrm{C}_{2}^{+}$ and $\mathrm{F}_{2}^{-}$ are paramagnetic.
(4) The specics $\mathrm{II}_{2}^{-}, \mathrm{C}_{2}^{+}$ and $\mathrm{F}_{2}$ are diamagnctic.

Kajal Gautam

Numerade Educator

Problem 126

Which of the following statement is false?
(1) During $\mathrm{N}_{2}^{+}$ formation, one electron each is removed from the bonding MOs.
(2) During $\mathrm{O}_{2}^{+}$ formation, one electron each is removed from the anti-bonding MOs.
(3) During $\mathrm{O}_{2}^{-}$ formation one electron each is added to the bonding MOs.
(4) During $\mathrm{II}_{2}-$ formation one electron each added to the antibonding MOs.

Hunza Gilgit

Numerade Educator

Problem 127

Which of the following statements is not correct regarding bonding MOs?
(1) Bonding MOs possess less energy than the atomic orbitals from which they are formed.
(2) Bonding MOs have low electron densities between the nuclei.
(3) Every electron in bonding MO contributes to the attraction between atoms.
(4) They are formed when the lobes of the combining atomic orbitals overlap.

Hunza Gilgit

Numerade Educator

Problem 128

Which of the following combinations is not allowed in the LC $\Lambda O$ method for the formation of a MO (consider the $z$ -axis as the molecular axis??
(1) $\mathrm{s}+\mathrm{p}_{2}$
(2) $\mathrm{s}-\mathrm{p}_{x}$
(3) $\mathrm{p}_{x}-\mathrm{p}_{x}$
(4) $\mathrm{p}_{2}+\mathrm{p}_{z}$

Hunza Gilgit

Numerade Educator

Problem 129

The energy of $2 \mathrm{~s}$ is greater than $\sigma^{*} 1 \mathrm{~s}$ orbital because
(1) $\sigma 2 \mathrm{~s}$ -orbital is bigger than $\sigma$ /s-orbital.
(2) $\sigma 2 \mathrm{~s}$ is a bonding orbital, whereas $\left.\sigma^{*}\right] \mathrm{s}$ an antibonding orbital.
(3) $\sigma 2 \mathrm{~s}$ orbital has a greater value of $n$ that $\sigma * 2 \mathrm{~s}$ -orbital.
(4) $\sigma 2 \mathrm{~s}$ orbital is formed only after $\sigma \mid \mathrm{s}$.

Hunza Gilgit

Numerade Educator

Problem 130

The bond length of $\mathrm{II}_{2}^{-}, \mathrm{II}_{2}^{-}$ and $\mathrm{II}_{2}$ are in the order
(1) $\mathrm{II}_{2}^{-}>\mathrm{II}_{2}>\mathrm{II}_{2}^{-}$
(2) $\mathrm{II}_{2}>\mathrm{II}_{2}^{-}>\mathrm{II}_{2}^{-}$
(3) $\mathrm{H}_{2}^{-}>\mathrm{H}_{2}>\mathrm{H}_{2}^{+}$
(4) $\mathrm{H}_{2}^{-}>\mathrm{H}_{2}^{-}>\mathrm{H}_{2}$

Hunza Gilgit

Numerade Educator

Problem 131

$\mathrm{N}_{2}$ and $\mathrm{O}_{2}$ are converted into monoanions $\mathrm{N}_{2}^{-}$ and $\mathrm{O}_{2}^{-}$, respectively. Which of the following statements is wrong?
(1) In $\mathrm{N}_{2}, \mathrm{~N}-\mathrm{N}$ bond weakens.
(2) In $\mathrm{O}_{2}^{-}, \mathrm{O}-\mathrm{O}$ bond order increascs.
(3) In $\mathrm{O}_{2}^{-}, \mathrm{O}-\mathrm{O}$ bond order decreases.
(4) $\mathrm{N}_{2}^{-}$ becomes paramagnetic.

Hunza Gilgit

Numerade Educator

Problem 132

The nodal plane in the $\pi$ -bond of ethene is located in
(1) the molecular plane
(2) a plane perpendicular to the molecular plane which bisects the carbon carbon sigma bond at right angle
(3) a plane parallel to the molecular plane
(4) a plane perpendicular to the molecular plane which contains the carbon carbon $\sigma$ -bond

Hunza Gilgit

Numerade Educator

Problem 133

Anti-bonding $\mathrm{MO}$ is formed by
(1) addition of atomic orbitals
(2) subtraction of atomic orbitals
(3) multiplication of atomic orbitals
(4) none of these

Hunza Gilgit

Numerade Educator

Problem 134

In which of the following pair or pairs is the stronger bond found in the first species?
(1) $\mathrm{O}_{2}, \mathrm{O}_{2}$
(II) $\mathrm{N}_{2}, \mathrm{~N}_{2}^{\prime}$
(III) NO, NO
(1) $\mathrm{I}$ only
(2) II only
(3) I and III only
(4) I, II and 111

Hunza Gilgit

Numerade Educator

Problem 135

Which of the following MO has two nodal planes perpendicular to cach other?
(1) $\sigma 2 \mathrm{~s}$
$(2) \pi 2 p_{x}$
(3) $\pi^{*} 2 \mathrm{p}_{y}$
(4) $\sigma^{*} 2 \mathrm{p}_{2}$

Hunza Gilgit

Numerade Educator

Problem 136

Ice has an open structure compared to water due to which it floats on water and occupies a greater volume of space. The open structure of ice is due to
(1) solid state of ice
(2) its low density
(3) crystalline nature
(4) hydrogen bonding

Hunza Gilgit

Numerade Educator

Problem 137

Which of the following statement is false?
(1) The boiling point of a compound is raised by intermolecular hydrogen bonding.
(2) o-nitrophenol is more volatile than p-nitrophenol because of intramolecular hydrogen bonding.
(3) Lower alcohols such as methanol and ethanol arc miscible in water due to hydrogen bonding.
(4) Intramolecular hydrogen bond enhances the boiling point.

Hunza Gilgit

Numerade Educator

Problem 138

The bydrogen bond is strongest in
(1) $\mathrm{O}-\mathrm{H} \ldots . \mathrm{S}$
(2) $\mathrm{S}-\mathrm{H} \ldots \ldots \mathrm{O}$
(3) $\mathrm{F}-\mathrm{H} \ldots \mathrm{F}$
(4) $\mathrm{F}-\mathrm{H}, \ldots \mathrm{O}$

Hunza Gilgit

Numerade Educator

Problem 139

The pair likely to form the strongest hydrogen bonding is
(1) $\mathrm{II}_{2} \mathrm{O}_{2}$ and $\mathrm{II}_{2} \mathrm{O}$
(2) IICOOII and $\mathrm{CII}_{3} \mathrm{COOII}$
(3) $\mathrm{CII}_{3} \mathrm{COOII}$ and $\mathrm{CII}_{3} \mathrm{COOCII}_{3}$
(4) $\mathrm{SiII}_{4}$ and $\mathrm{SiCl}_{4}$

Hunza Gilgit

Numerade Educator

Problem 140

The maximum possible number of hydrogen bonds in which a water molecule can participate is
(1) 4
(2) 3
(3) 2
(4) 6

Hunza Gilgit

Numerade Educator

Problem 141

The false statement among the following is
(1) Bond energy of covalent $0-H$ bond in water is greater than bond energy of hydrogen bond.
(2) The intermolecular attractive forces vary in the order: water $>$ ether $>$ alcohol.
(3) The high heat of vapourisation of water is due to hydrogen bonding.
(4) Acetic acid exists as a dimer in benzene due to hydrogen bonding.

Hunza Gilgit

Numerade Educator

Problem 142

The predominant intermolecular forces in hydrogen fluoride is due to
(1) Dipole-induced dipole interaction
(2) Dipole dipole interaction
(3) Hydrogen bond formation
(4) Dispersion interaction

Hunza Gilgit

Numerade Educator

Problem 143

Which of the following does not change as a consequence of hydrogen bonding in a compound?
(1) colour
(2) boiling point
(3) density
(4) freezing point

Hunza Gilgit

Numerade Educator

Problem 144

The hydrogen bonding in oxygen compounds is more significant than that in sulphur compounds because oxygen is
(1) a very small atom compared to the sulphur atom
(2) more electroncgative than sulphur
(3) more reactive than sulphur
(4) a gas where as sulphur is a solid at room temperature

Hunza Gilgit

Numerade Educator

Problem 145

There is no hydrogen bonding in $\mathrm{CH}_{4}$ unlike in $\mathrm{H}_{2} \mathrm{O}$ because
(1) $\mathrm{C}$ is not sufficiently electronegative to be linked by hydrogen bonds.
(2) Catom is bigger than $\mathrm{O}$ atom.
(3) $\mathrm{C}$ in $\mathrm{CH}_{4}$ has no lone pair of electrons.
(4) $\mathrm{CH}_{4}$ is bigger than $\mathrm{H}_{2} \mathrm{O}$.

Hunza Gilgit

Numerade Educator

Problem 146

Which one of the following about hydrogen bonding is false?
(1) It alters some of the physical propertics of the compound.
(2) Notall II-compounds can have hydrogen bonding.
(3) The II-atom in a hydrogen bonded pair of atoms is equidistant from the atoms.
(4) Hydrogen bond is a week bond.

Hunza Gilgit

Numerade Educator

Problem 147

Arrange the following in the decreasing order of hydrogen bonding $\mathrm{CH}_{4}, \mathrm{CH}_{3} \mathrm{OH}, \mathrm{CH}_{3} \mathrm{~F}$ and $\mathrm{CH}_{3} \mathrm{NH}_{2}$.
(1) $\mathrm{CII}_{3} \mathrm{OII}>\mathrm{CII}_{3} \mathrm{NII}_{2}>\mathrm{CII}_{3} \mathrm{~F}>\mathrm{CII}_{4}$
(2) $\mathrm{CII}_{3} \mathrm{OII}>\mathrm{CII}_{3} \mathrm{\Gamma}>\mathrm{CII}_{3} \mathrm{NII}_{2}>\mathrm{CII}_{4}$
(3) $\mathrm{CII}_{3} \mathrm{~F}>\mathrm{CII}_{3} \mathrm{OII}>\mathrm{CII}_{3} \mathrm{NII}_{2}>\mathrm{CII}_{4}$
(4) $\mathrm{CII}_{4}>\mathrm{CII}_{3} \mathrm{~F}>\mathrm{CII}_{3} \mathrm{NII}_{2}>\mathrm{CII}_{3} \mathrm{OII}$

Hunza Gilgit

Numerade Educator

Problem 148

The melting point of 2 -nitrophenol is lower than that of 4 -nitrophenol and this is because of
(1) Intramolecularhydrogen bondingin 2-nitrophenol
(2) Intramolecular hydrogen bonding in 4 -nitrophenol
(3) Intermolecular hydrogen bonding in 2 -nitrophenol
(4) Hydrogen bonding has no relation to the melting point,

Hunza Gilgit

Numerade Educator

Problem 149

The hydrogen bond length is minimum in
(1) HF
(2) $\mathrm{H}_{2} \mathrm{O}$
(3) $\mathrm{H}_{2} \mathrm{~S}$
(4) $\mathrm{CH}_{3} \mathrm{COOH}$

Hunza Gilgit

Numerade Educator

Problem 150

The relative strength of the hydrogen bond between the molecules in liquid hydrogen halides can be best ascertained by a comparison of their
(1) bond dissociation energies
(2) enthalpy changes of vapourisation
(3) freezing points
(4) enthalpy changes of formation

Hunza Gilgit

Numerade Educator

Problem 151

Although nitrogen and chlorine have the same electroncgativity, nitrogen atoms form stronger hydrogen bonds than chlorine atoms. This is due to
(1) the basic character of nitrogen
(2) the smaller size of nitrogen
(3) the lesset number of electrons in the nitrogen atom
(4) the inertness of nitrogen atom

Hunza Gilgit

Numerade Educator

Problem 152

Hydrogen bonding is exhibited by
(1) all the molecules containing H-atom
(2) molecules in which tuo H-atoms are present
(3) molecules in which H-atom is covalently bonded to $\mathrm{F}, \mathrm{O}, \mathrm{N}$
(4) molecules in which $\mathrm{H}$ -atom is bonded to atoms with electronegativity more than $2.1$

Hunza Gilgit

Numerade Educator

Problem 153

The normal boiling points of $\mathrm{CS}_{2}, \mathrm{II}_{2} \mathrm{O}$ and $\mathrm{CCl}_{4}$ are $41.3^{\circ} \mathrm{C}, 100^{\circ} \mathrm{C}$ and $77^{\circ} \mathrm{C}$, respectively. In which liquid the intermolecular forces are the weakest?
(1) $\mathrm{CCl}_{4}$
(2) $\mathrm{H}_{2} \mathrm{O}$
(3) $\mathrm{CS}_{2}$
(4) all are equal

Hunza Gilgit

Numerade Educator

Problem 154

4o-nitrophenol is stcam volatile, whercas $\mathrm{p}$ -nitrophenol is not. This is due to
(1) intramolecular hydrogen bonding present in orthonitrophenol
(2) intermolecular hydrogen bonding present in orthonitrophenol
(3) intermolecular hydrogen bonding present in paranitrophenol
(4) nonc of these

Hunza Gilgit

Numerade Educator

Problem 155

Organic compounds soluble in water contain
(1) C, H, CI
(2) $\mathrm{C}_{+} \mathrm{H}$
(3) $\mathrm{C}, \mathrm{H}, \mathrm{O}$
(4) $\mathrm{C}, \mathrm{s}$

Hunza Gilgit

Numerade Educator

Problem 156

Hydrogen bonds are formed between moleculcs in which hydrogen is covalently bonded to an clcment whose atomic radius and electroncgativity respectively are
(1) large and low
(2) large and high
(3) small and high
(4) small and low

Hunza Gilgit

Numerade Educator

Problem 157

Pick out the property which is not relevant, In a molecule, hydrogen bond results in
(1) molecule association
(2) abnormal boiling points
(3) high solubility value
(4) high Van der Waal's forces

Hunza Gilgit

Numerade Educator

Problem 158

Which of the following statement is wrong?
(1) Bond length decreases with increase in $\mathrm{p}$ -character,
(2) Bond energy of $\mathrm{HF}$ is the highest among hydrogen halides.
(3) Bond energy decreases with increase in the lone pair electrons on bonded atoms.
(4) Bond energy of a covalent bond increases with increase in the difference of electronegativities of bonded atoms.

Hunza Gilgit

Numerade Educator

Problem 159

Average bond energy values can be used to calculate
(1) the energy content of the molecule
(2) heat of formation
(3) heat of reaction
(4) all

Hunza Gilgit

Numerade Educator

Problem 160

The term bond energy and dissociation energy
(1) always have the same meaning
(2) always have different meaning
(3) have no correlation with each other
(4) are same only for diatomic molecules

Hunza Gilgit

Numerade Educator

Problem 161

In the series ethane, ethaneand cthyne the C-II bond energy is
(1) the same in all the three compounds
(2) greatest in ethane
(3) greatest in ethene
(4) greatest in ethyne

Hunza Gilgit

Numerade Educator

Problem 162

The heat of formation of $\mathrm{CII}_{4}$ is $360 \mathrm{k}$.cal. The heat of formation of $\mathrm{C}_{2} \mathrm{II}_{6}$ is $620 \mathrm{k}$.cal. The C-C bond energy is
(1) $80 \mathrm{kCal}$
(2) $90 \mathrm{kCal}$
(3) $100 \mathrm{kCal}$
(4) $120 \mathrm{kCal}$

Hunza Gilgit

Numerade Educator

Problem 163

The order of relative strengths of bonds formed by sp, $\mathrm{sp}^{2}$ and $\mathrm{sp}^{3}$ hybrid orbitals is
(1) $\mathrm{sp}>\mathrm{sp}^{2}>\mathrm{sp}^{3}$
(2) $\mathrm{sp}<\mathrm{sp}^{2}<\mathrm{sp}^{3}$
(3) $\mathrm{sp}=\mathrm{sp}^{2}=\mathrm{sp}^{3}$
(4) $\mathrm{sp}<\mathrm{sp}^{2}>\mathrm{sp}^{3}$

Hunza Gilgit

Numerade Educator

Problem 164

The F-F bond in $\mathrm{F}_{2}$ is weak because of
(1) the high electronegativity of fluorine
(2) the small size of fluorine and the repulsion between the lone pairs of electrons in adjacent atoms
(3) fluorine being the first member of the halogen family
(4) the reactivity of fluorine

Hunza Gilgit

Numerade Educator

Problem 165

Energy required to dissociate $4 \mathrm{~g}$ of gascous hydrogen into free gascous atoms is $208 \mathrm{kCal}$ at $25^{\circ} \mathrm{C}$. The bond energy of II-II is
(1) $104 \mathrm{kCal}$
(2) $208 \mathrm{k} \mathrm{Cal}$
(3) $52 \mathrm{kCal}$
(4) $4 \mathrm{kCal}$

Hunza Gilgit

Numerade Educator

Problem 166

The average bond energy of C-C bond is $342 \mathrm{KJ}$ mol $^{1}$. The bond energy of Si-Si bond is
$(1)=342 \mathrm{KJ}$ mol $^{\prime}$
(2) $<342 \mathrm{KJ}$ mol 1
(3) $>342 \mathrm{KJ}$ mol
(4) cannot be predicted

Hunza Gilgit

Numerade Educator

Problem 167

If the bond distance in $\mathrm{H}_{2}$ is $r_{1}$ and $\mathrm{Cl}_{2}$ is $r_{2}$, the bond distance in $\mathrm{HCl}$ is
(1) $r_{1}+r_{2}$
(2) $r_{1} / r_{2}$
(3) $\frac{r+r_{2}}{2}$
(4) $\frac{\frac{r_{1}}{2}+\frac{r_{2}}{2}}{2}$

Hunza Gilgit

Numerade Educator

Problem 168

Bond length decreases with
(1) increase in size of the atom
(2) increase in the number of bonds between atoms
(3) decrease in the number of bonds between atoms
(4) decrease in bond angle

Hunza Gilgit

Numerade Educator

Problem 169

The correct order of the arrangement of bond length is
(1) $\mathrm{F}_{2}>\mathrm{N}_{2}>\mathrm{Cl}_{2}>\mathrm{O}_{2}$
(2) $\mathrm{Cl}_{2}>\mathrm{F}_{2}>\mathrm{O}_{2}>\mathrm{N}_{2}$
(3) $\mathrm{O}_{2}>\mathrm{Cl}_{2}>\mathrm{N}_{2}>\mathrm{F}_{2}$
(3) $\mathrm{F}_{2}>\mathrm{Cl}_{2}>\mathrm{N}_{2}>\mathrm{O}_{2}$

Hunza Gilgit

Numerade Educator

Problem 170

The correct order of the O-O bond length in $\mathrm{O}_{2}, \mathrm{H}_{2} \mathrm{O}_{2}$ and $\mathrm{O}_{3}$ is
(1) $\mathrm{O}_{2}>\mathrm{O}_{3}>\mathrm{II}_{2} \mathrm{O}_{2}$
(2) $\mathrm{O}_{3}>\mathrm{II}_{2} \mathrm{O}_{2}>\mathrm{O}_{2}$
(3) $\mathrm{II}_{2} \mathrm{O}_{2}>\mathrm{O}_{3}>\mathrm{O}_{2}$
(4) $\mathrm{O}_{2}>\mathrm{II}_{2} \mathrm{O}_{2}>\mathrm{O}_{3}$

Hunza Gilgit

Numerade Educator

Problem 171

Which of the following is not correct?
(1) Among $\mathrm{CHCl}_{3}, \mathrm{SiCl}_{4}, \mathrm{SnCl}_{2}$ and $\mathrm{NH}_{3}$, the non-
polar molecule is $\mathrm{SiCl}_{4}$
(2) Among $\mathrm{CO}_{2}, \mathrm{SO}_{2}, \mathrm{H}_{2} \mathrm{O}$ and $\mathrm{NH}_{3}$, the one with
zero dipole moment is $\mathrm{CO}_{2}$.
(3) Among $\mathrm{CH}_{3} \mathrm{Cl}, \mathrm{CH}_{2} \mathrm{Cl}_{2}, \mathrm{CHCl}_{3}$ and $\mathrm{CCl}_{4}$, the one
with maximum dipole moment is $\mathrm{CHCl}_{3}$.
(4) \Lambdamong C1-F, F-F, Br-F and Br-C1, the strongest bond is Br- $\Gamma$.

Hunza Gilgit

Numerade Educator

Problem 172

$\mathrm{NH}_{3}$ has a net dipole moment but boron trifluoride has zero dipole moment because
(1) $\mathrm{B}$ is less electronegative than $\mathrm{N}$
(2) $\mathrm{F}$ is more electronegative than $\mathrm{H}$
(3) $\mathrm{BF}_{3}$ is pyramidal while $\mathrm{NH}_{3}$ is planar
(4) $\mathrm{BF}_{3}$ is trigonal planar while $\mathrm{NII}_{3}$ is pyramidal

Hunza Gilgit

Numerade Educator

Problem 173

Which of the following statements is wrong?
(1) HCl molecule in the vapour state is an example of polar covalent bond.
(2) Among $\mathrm{CH}_{2} \mathrm{Cl}_{2}, \mathrm{BF}_{3}, \mathrm{NF}_{3}$ and $\mathrm{ClO}_{2}$, only $\mathrm{BF}_{3}$
has zero dipole moment.
(3) The dipole moment of $\mathrm{NH}_{3}$ is less than $\mathrm{NCl}_{3}$.
(4) Anhydrous IICl is a bad conductor of clectricity but aqueous IIC1 is a good conductor.

Hunza Gilgit

Numerade Educator

Problem 174

The correct order of decreasing dipole moment is
(1) $\mathrm{HF}>\mathrm{SO}_{2}>\mathrm{H}_{2} \mathrm{O}>\mathrm{NH}_{3}$
(2) $\mathrm{HF}>\mathrm{H}_{2} \mathrm{O}>\mathrm{SO}_{2}>\mathrm{NH}_{3}$
(3) $\mathrm{HF}>\mathrm{NH}_{3}>\mathrm{SO}_{2}>\mathrm{H}_{2} \mathrm{O}$
(4) $\mathrm{II}_{2} \mathrm{O}>\mathrm{NII}_{3}>\mathrm{SO}_{2}>\mathrm{IIF}$

Hunza Gilgit

Numerade Educator

Problem 175

The electronegativity values of $\mathrm{C}, \mathrm{H}, \mathrm{O}, \mathrm{N}$ and $\mathrm{S}$ are $2.5,2.1,3.5,3.0$ and $2.5$, respectively. Which of the following bonds is most polar?
(1) $\mathbf{C}-\mathrm{H}$
(2) $\mathrm{N}-\mathrm{H}$
(3) $\mathrm{S}-\mathrm{H}$
(4) O-H

Hunza Gilgit

Numerade Educator

Problem 176

Which bond angle would result in the maximum dipole moment for the triatomic molecule $X Y Z$ shown below?
(1) $\theta=90^{\circ}$
(2) $\theta=120^{\circ}$
(3) $\theta=150^{\circ}$
(4) $\theta=180^{\circ}$

Kajal Gautam

Numerade Educator

Problem 177

The bonds between $\mathrm{P}$ atoms and $\mathrm{Cl}$ atoms in $\mathrm{P} \mathrm{Cl}_{5}$ are likely to be
(1) ionic with no covalent character
(2) covalent with some ionic character
(3) covalent with no ionic character
(4) ionic with some metallic character

Hunza Gilgit

Numerade Educator

Problem 178

Which have zero dipole moment?
(1) 1,1 dichloroethane
(2) cis-1,2-dichloroethane
(3) trans- 1,2 -dichloroethane
(4) none

Hunza Gilgit

Numerade Educator

Problem 179

Dipole moment is exhibitcd by
(1) 1,4 -dichlorobenzenc
(2) 1,2 -dichlorobenzene
(3) trans-1,2-dichlorocthane
(4) trans-2,3-dichloro 2-butene

Hunza Gilgit

Numerade Educator

Problem 180

If a molecule of $M X_{3}$ has zero dipole moment, the sigma bonding orbitals used by $M$ (At, No. $<21)$ is
(1) purce $\mathrm{p}$
(2) sp hybrid
(3) sp $^{2}$ hybrid
(4) $\mathrm{sp}^{3}$ bybrid

Hunza Gilgit

Numerade Educator

Problem 181

A molecule containing polar bonds is nonpolar, this is becaluse of
(1) small sizes of atoms in the molecule
(2) big sizes of atoms in the molecule
(3) the atoms in it being highly electronegative
(4) the vector cancellation of the bond moments

Hunza Gilgit

Numerade Educator

Problem 182

$\mathrm{H}_{2} \mathrm{O}$ has net dipole moment while $\mathrm{BeF}_{2}$ has zero dipole moment because
(1) $\mathrm{H}_{2} \mathrm{O}$ molecule is linear while $\mathrm{Be} \mathrm{F}_{2}$ is bent
(2) $\mathrm{BeF}_{2}$ molecule is linear while $\mathrm{H}_{2} \mathrm{O}$ is bent
(3) Fluorine is more electronegative than oxygen
(4) Be is more electronegative than oxygen

Hunza Gilgit

Numerade Educator

Problem 183

Which of the following is wrong?
(1) Among I-F, I-Br, $\mathrm{N}-\mathrm{H}$ and $\mathrm{N}-\mathrm{Cl}$, the nonpolar one is $[-B r$.
(2) The highest polar bond among $\mathrm{F}-\mathrm{O}, \mathrm{C}-\mathrm{S}, \mathrm{Cl}-\mathrm{Br}$
and $\mathrm{N}-\mathrm{H}$ is $\mathrm{N}-\mathrm{H}$.
(3) $\mathrm{F}_{2}$ molecule is nearly $100 \%$ covalent.
(4) A triatomic molecule must be either linear with a bond angle $180^{\circ}$ or bent.

Hunza Gilgit

Numerade Educator

Problem 184

Which of the following statement is falsc?
(1) The measurement of dipole moment of a gaseous diatomic molecule is a direct indication of bond polarity.
(2) For a polyatomic molecule, its dipole moment is determined only from bond moments.
(3) $\mathrm{SO}_{2}$ is nonlinear and as a consequence it should have dipole moment,
(4) Lone pair of electrons present on central atom can give rise to dipole moment.

Hunza Gilgit

Numerade Educator

Problem 185

Which of the following is incorrect?
(1) The unit of dipole moment is Debyc, i.c., $10^{-18}$ esu $\mathrm{cm}$.
(2) Dipole moment is a vector quantity.
(3) Decrease in bond angle of triatomic polar molccule decreascs the dipole momcnt.
(4) Dipole moment can be used to calculate the magnitude of charge on an atom in a polar molecule.

Hunza Gilgit

Numerade Educator

Problem 186

Resonance structures of a molecule should have
(1) nearly the same energy contents
(2) same number of paired electrons
(3) identical arrangement of atoms
(4) all

Hunza Gilgit

Numerade Educator

Problem 187

Which of the following is not characteristic of resonance?
(1) The chemical structure shows the constituent atoms in the same relative position.
(2) They have nearly the same energy.
(3) They have the same number of unpaired electrons.
(4) The actual structure can be represented on paper using conventional symbols.

Hunza Gilgit

Numerade Educator

Problem 188

The different forms of a molecule having different arrangement of atoms arc called
(1) Tautomers
(2) Isomers
(3) Canonical forms
(4) $\mathrm{Al} 1$

Hunza Gilgit

Numerade Educator

Problem 189

Resonating forms of a molecule can
(1) be isolated
(2) cannot be isolated
(3) either (1) or (2)
(4) none

Hunza Gilgit

Numerade Educator

Problem 190

The relatively unimportant contributing structure in case of $\mathrm{II}_{3} \mathrm{~N}$ is
(1) $\mathrm{H}-\ddot{\mathrm{N}}=\mathrm{N}^{+}=\overline{\mathrm{N}}$
(2) $\mathrm{H}-\ddot{\mathrm{N}}-\mathrm{N}^{+} \equiv \mathrm{N}:$
(3) $\mathrm{II}-\mathrm{N}^{\prime} \equiv \mathrm{N}-\ddot{\mathrm{N}}:$
(4) Nonc

Hunza Gilgit

Numerade Educator

Problem 191

The correct statement about resonating structure is
(1) They have no real existence.
(2) These are hypothetical structures.
(3) These structures can never be separated.
(4) All are correct.

Hunza Gilgit

Numerade Educator

Problem 192

A molecule may be represented by three structures having energies $E_{1}, E_{2}$ and $E_{3}$, respectively. The energies of these structures follow the order $E_{3}<E_{2}<E_{1}$, respectively. If the experimental bond energy of the molecule is $E_{0}$, the resonance energy is
(1) $\left(E_{1}+E_{2}+E_{3}\right)-E_{0}$
(2) $E_{0}-E_{3}$
(3) $E_{0}-E_{2}$
(4) $E_{0}-E_{1}$

Kajal Gautam

Numerade Educator

Problem 193

Which of the following conditions is not correct for resonating structures?
(1) The contributing structures must have the same number of unpaired electrons.
(2) The contributing structures should have similar energies.
(3) The contributing structures should be so written that unlike charges reside on atoms that are far apart.
(4) The positive charge should be present on the electropositive clement and the negative charge on the electroncgative clement.

Hunza Gilgit

Numerade Educator

Problem 194

Which is not true for resonance?
(1) Canonical forms differ only in electronic arrangement.
(2) Canonical forms differ in atomic as well as electronic arrangement.
(3) Canonical forms have the same number of unpaired electrons.
(4) Cannnical forms are hypothetical.

Hunza Gilgit

Numerade Educator

Problem 195

Resonance structures can be written for
(1) $\mathrm{O}_{3}$
(2) $\mathrm{NH}_{3}$
(3) $\mathrm{CH}_{4}$
(4) $\mathrm{H}_{2} \mathrm{O}$

Hunza Gilgit

Numerade Educator

Problem 196

Which of the following do not have resonance structures?
(1) $\mathrm{CO}_{3}^{2}$
(2) $\mathrm{NO}_{3}$
(3) $\mathrm{NH}_{3}$
(4) $\mathrm{BF}_{3}$

Hunza Gilgit

Numerade Educator