CHEMICAL BONDING AND MOLECULAR STRUCTURE – 3
1) In a homonuclear molecule which of the following set of orbitals are degenerate?
2) Which one of the following molecules is not linear?
3) According to the molecular orbital theory possesses a
a) Bond order of 2.5
b) Three unpaired electrons
c) Diamagnetic character
d) Stability lower than that of the oxygen molecule
4) Which of the following properties would suggest that a compound under investigation is covalent?
a) It conducts electricity on melting
b) It is a non-electrolyte
c) It has high melting point
d) It is a compound of a metal and a non-metal.
5) Bond lengths in the species are in the order
d) None of the above
6) Among LiCl, BeCl2, BCl3 and CCl4 the covalent bond character follows the order
7) The complex ion is formed by hybridisation. Hence the ion should possess
a) Octahedral geometry
b) Tetrahedral geometry
c) Square planar geometry
d) Tetragonal geometry
8) Which statement is not correct?
a) a sigma bond is weaker than a pi-bond
b) A sigma bond is stronger than a Pi-bond
c) A double bond is stronger than a single bond
d) A double bond is shorter than a single bond
9) Which one shows maximum hydrogen bonding?
10) A linear combination of two hybridized orbitals belonging to two atoms and each having one electron leads to a
a) Sigma bond
b) Double bond
c) Co-ordinate covalent bond
d) Pi- bond
11) The M O configuration of will be
12) The bond order for a species with the configuration will be
13) has a higher boiling point than expected because
b) It has strong intermolecular hydrogen bonding
c) It has intramolecular hydrogen bonds
d) Its density decreases on freezing
14) Which of the following has a net dipole moment?
15) Which one of the following has the least bond angle?
16) What type of hybridization is possible in square planar molecules?
17) Intermolecular forces in solid hydrogen are
a) van der Waal’s forces
b) Covalent bonds
c) Hydrogen bonds
d) None of these
18) Which is not a linear molecule?
19) The element with the electronic configuration is
a) Only trivalent
b) Only tetravalent
c) Only pentavalent
d) Trivalent and pentavalent
20) In compound X, all the bond angles are exactly . X is
b) Carbon tetrachloride
21) Which one of the following has the shortest carbon bond length?
22) Which type of bonds are not present in molecule?
c) Ionic bond
d) Ionic as well as co-ordinate
23) Which structure is linear?
24) The correct order of increasing ionic character is
25) Both hybrid carbons are present in which one of the following compounds?
26) Which one of the following is paramagnetic?
27) The type of bonding in HCl molecule is
a) Pure covalent bond
b) Polar covalent
c) highly polar
d) Hydrogen bonding
28) Which one of the following does not exhibit paramagnetism?
29) The percentage of s- character in the hybrid orbitals, sp, follows the pattern
30) Among the following, which compound will show the highest lattice energy?
31) Which one of the following is the correct order of interactions?
a) covalent < hydrogen-bonding < van der Waal’s < dipole-dipole
b) van der Waal’s < hydrogen-bonding < dipole-dipole < covalent
c) van der Waal’s < dipole-dipole < hydrogen-bonding < covalent
d) dipole-dipole < van der Waal’s < hydrogen-bonding < covalent
32) Amongst Licl, RbCl, , the compounds with the greatest and the least ionic character respectively are
a) LiCl and RbCl
b) RbCl and BeCl2
33) Which of the following has a bond formed by the overlap of orbitals?
34) Which of the following has zero dipole moment?
35) Two lone pairs of electrons and two bond pairs of electrons are present in
36) The central atom assumes the hybridization in
37) has a much higher boiling point than because
a) NH3 has a larger molecular weight
b) NH3 undergoes umbrella inversion
c) NH3 forms hydrogen bonds
d) NH3 contains ionic bonds whereas PH3 contains covalent bonds
38) Which of the following has net dipole moment?
39) The octet rule is not valid for the molecule`
40) Which of the following structures is expected to have three bond pairs and one lone pair?
b) Trigonal planar
41) Consider two elements with atomic numbers 37 and 53; the bond between their atoms would be
42) If 2 elements have electronegativities 1.2 and 3.0, the bond formed between them would be
43) The sulphuric acid molecule contains
a) Only covalent bonds
b) Covalent and ionic bonds
c) Covalent and co-ordinate bonds
d) Covalent, ionic and co-ordinate bonds
44) Which of the following will have a low heat of fusion ?
a) a covalent solid
b) a metallic solid
c) An ionic solid
d) A molecular solid
45) Ethanol and methoxy-methane have the same molecular weight but methoxy methane boils at a lower temperature because it has
a) low density
b) no hydrogen bonding
c) molecular association
d) Oxygen atom attached to two methyl groups
46) The elements X of the group VA combine with the element Y of group VIB. The resulting compound may have the formula
47) The bond angle is maximum for
48) The compound which contains both ionic and covalent bonds is
49) What happens if is treated with ?
a) A white ppt. of AgCl will form
50) A crystal will be hard and have a high melting point if it is a
a) Covalent crystal
b) Ionic crystal
c) Metallic crystal
d) Molecular crystal
51) The most favorable conditions for ionic bonding are
a) Low charge on ions, a large cation, a large anion
b) Low charge on ions, a large cation and a small anion
c) High charge on ions, a large cation and a small anion
d) High charge on ions, a small cation, a large anion
52) The dielectric constant of is 80. The electrostatic force of attraction between will be
a) reduced to 1/40 in water than in air
b) reduced to 1/80 in water than in air
c) will be increased to 80 times in water than in air.
d) Will remain unchanged
53) Mark the incorrect statement in the following.
a) The bond order in the species O2, O2+, and O2– decreases as O2+ < O2 < and O2_
b) the bond energy in a diatomic molecule always increases when an electron is lost
c) electrons in antibonding M O contribute to repulsion between two atoms.
d) With the increase in bond order, bond length decreases and bond strength increases.
54) Which of the following does not have a tetrahedral structure?
55) Which of the following pairs will form the most stable bond?
a) Na and Cl
b) Mg and F
c) Li and F
d) Na and F
56) Among the following orbital bonds, the angle is minimum between
b) px and py orbitals
c) H-OH in water
d) sp bonds
57) Linus Pauling received the Nobel Prize for his work on
a) atomic structure
c) Chemical bonding
58) Hydrogen bonding is maximum
a) Ethyl chloride
d) Diethyl ether
59) The distance between two adjacent carbon atoms is largest in
60) On the basis of the concept of ionic potential, the tendency to form covalent bonds in a group
c) Remains unchanged
d) Shows erratic change
61) According to Fajans rule covalent bonding is favorable between
a) a small cation and an large anion
b) a small cation and a small anion
c) a large cation and a large anion
d) a large cation and a small anion
62) The density of ice is less than that of water because of
a) extensive hydrogen bonding
b) crystal modification of ice
c) the open porous structure of ice due to hydrogen bonding
d) different physical states of ice and water
63) The bond order is a concept in the molecular orbital theory. It depends on the number of electrons in the bonding and anti bonding orbitals. Which of the following statements is true about the bond order ?
a) It cannot be a negative quantity
b) It always has an integral value
c) It can assume any value, positive or negative, integral or fractional including zero.
d) It is a non-zero quantity.
64) Which one of the following molecules is paramagnetic?
65) Which one of the following hydrogen halides has the lowest boiling point?
66) Which concept best explains the fact that o-nitrophenol is more volatile than p- nitrophenol?
c) Hydrogen bonding
d) Steric hindrance
67) The round state electronic configuration of valence shell electrons in nitrogen molecule is written as . Hence the bond order of the nitrogen molecule is
68) Which of the following species is paramagnetic?
69) is iso-structural with which of the following?
70) The sulphate of a metal has the formula . The formula of its phosphate will be
71) The structure of molecule is
b) Square planar
c) Trigonal bipyramidal
d) Pentagonal bipyramidal
72) The bond order of the NO molecule is
73) According to the VSEPR theory, the most probable shape of the molecule having 4 electron pairs in the outer shell of the central atom is
74) Which of the following is the correct electron dot structure of the molecule?
75) Which of the following has the least covalent P-H bond?
76) Which of the following has hybridization?
77) The structure and hybridisation of Si(CH3)4 is
a) bent, sp
78) Among the following species, identify the isostructural pairs
79) KF contains with HF to form . The compound contains the species
80) Which of the following molecule is not linear in shape?
81) Bonding in ferric chloride is
d) None of the above
82) has an abnormally high boiling point because it has
a) an alkaline nature
b) a distorted shape
d) Hydrogen bonding
83) In which of the following pairs is hydrogen bonding not possible?
84) The polarization power of a cation increases when the
a) charge on the cation increases
b) size of the cation increases
c) size of the cation decreases
d) none of the above
85) Which contains both polar and non-polar bonds?
86) Which of the following should be the most stable?
87) Which of the following cannot be formed?
88) Which of the following has the highest dipole moment?
89) The number of electrons that are paired in the oxygen molecule is
90) The molecule having a non-zero dipole moment is
91) Two ice cubes are pressed over each other until they unite to form one block. Which of the following forces dominated for holding them together?
a) Dipole-dipole interaction
b) van der Waal’s forces
c) Hydrogen bond formation
d) Covalent attraction
92) The compound is tetrahedral. The number of XMX angles formed in the compound is
93) The shape of gaseous is
94) Which of the following substances has the least ionic character?
95) r5Which of the following molecules will have an unequal P-F bond lengths?
96) The anti-bonding molecular orbital is formed by the
a) Addition of the wave functions of the atomic orbitals
b) Subtraction of the wave functions of the atomic orbitals
c) Multiplication of the wave functions of the atomic orbitals
d) None of these
97) Which of the following molecules is linear ?
98) Which of the following pairs of two molecules have identical bond orders?
99) The dipole moment of HBr is and inter-atomic spacing is . The % of ionic character of HBr is
100) Which of the following statements is incorrect about a solution?
a) A solution is always a homogeneous mixture
c) Brass cannot be called a solution
d) An ionic compound dissolves in water if the hydration energy is greater than lattice energy
Ans 1) b
Ans Desc 1) have equal energy and hence are degenerate.
Ans 2) b
Ans Desc 2) SO2 has sp2 hybridization and hence is not linear.
Ans 3) a
Ans Desc 3) B O in
Ans 4) b
Ans Desc 4) Covalent compounds are non-electrolytes
Ans 5) b
Ans Desc 5)
B O in
B O in
B O in
Now , smaller the bond order, larger the bond length. Thus options (b) is correct.
Ans 6) c
Ans Desc 6) As we move from Li® Be® B® C, the electronegativity (EN) increases and hence the EN difference between the element and Cl decreases and accordingly the covalent character increases
Ans 7) a
Ans Desc 7) According to VSEPR theory, a molecule with six bond pairs must be octahedral.
Ans 8) a
Ans Desc 8) A sigma bond is stronger than a pi- bond
Ans 9) d
Ans Desc 9)
Ans 10) a
Ans Desc 10) Linear combination of two hybridized orbitals leads to the formation of a sigma bond.
Ans 11) d
Ans Desc 11) has 4-1=3 electrons; two of which are present in .
Ans 12) b
Ans Desc 12)
Here, Nb= 2+2+1=5
Therefore, Bond order =(5-4)/2=1/2
Ans 13) b
Ans Desc 13)
Ans 14) c
Ans Desc 14) CCl4 has zero dipole moment due to symmetrical structure, BF3 has zero dipole moment due to triangular planar shape and CO2has zero dipole moment due to linear shape. NH3 has pyramidal structure and hence has a net dipole moment.
Ans 15) b
Ans Desc 15) Due to lp-lp repulsions, the bond angle in H2 O (104.50) is lower than that in NH3(1070) and CH4(1090 28). BeF2 , on the other hand, has sp-hybridization and hence has a bond angle of 1800.
Ans 16) c
Ans Desc 16) Square planar molecules have dsp2 hybridization.
Ans 17) a
Ans Desc 17) Intermolecular forces in solid H2 are van der Waals forces of attraction.
Ans 18) d
Ans Desc 18) Only H2 O is not linear while all the remaining molecules are linear.
Ans 19) d
Ans Desc 19) Trivalent or pentavalent such as in P4 O6 and P4 O10 respectively.
Ans 20) b
Ans Desc 20) All bond angles in CCl4 are 1090 28
Ans 21) c
Ans Desc 21) Because of the triple bond, the carbon Â–carbon bond distance in ethyne is shortest.
Ans 22) d
Ans Desc 22) H Â– O- N=O does not have ionic and co-ordinate bonds.
Ans 23) b
Ans Desc 23) CO2 has sp-hybridisation and is linear. SO2 and are planar ( sp2) while is tetrahedral (sp3).
Ans 24) a
Ans Desc 24) Electrornegativity difference between the element and Cl increases down the group and hence the ionic character increases accordingly. Thus option ( a) is correct,
Ans 25) d
Ans Desc 25)
Ans 26) b
Ans Desc 26)
No of electrons in
CN– = 6+7+1=14
Only has odd electrons and hence is paramagnetic.
Ans 27) b
Ans Desc 27) has polar covalent bonding.
Ans 28) d
Ans Desc 28)
Total number of electrons in
ClO2 = 17 + 2 x 8 = 33
Only has even number of electrons and hence is not paramagnetic.
Ans 29) b
Ans Desc 29) Percentage of s-character decreases as sp(50%)> sp2(33.3%) > sp3(25.0%).
Ans 30) b
Ans Desc 30) For compounds containing ions of same charge, lattice energy increases as the size of the ions decreases. Thus NaF has the highest lattice energy.
Ans 31) b
Ans Desc 31) The strength of the interactions follows the order: van der Waals< hydrogen-bonding < dipole-dipole < covalent.
Ans 32) b
Ans Desc 32) Electronegativity difference ( EN) is highest in RbCl( 3-0.8=2.2) and least in BeCl2 (3-1.5=1.5)
Ans 33) a
Ans Desc 33)
Ans 34) c
Ans Desc 34) SiF4 is a symmetrical tetrahedral molecule and hence its dipole moment is zero.
Ans 35) c
Ans Desc 35) H2 O has two lone pairs and two bond pairs.
Ans 36) a
Ans Desc 36) PCl3 has sp3 hybridization while all the remaining molecules have sp2 hybridization.
Ans 37) c
Ans Desc 37)
Ans 38) c
Ans Desc 38) NH3 is pyramidal shape and hence has a net dipole moment.
Ans 39) d
Ans Desc 39) The Lewis structure of CO is . Here C has only six electrons in its valence shell and hence the octet is not valid for CO.
Ans 40) c
Ans Desc 40) Pyramidal structures have three bond pairs, and one lone pair.
Ans 41) b
Ans Desc 41)
The element with atomic number (Z) 37 is an alkali metal ie; Rb and with atomic number (Z)=53 is a halogen, ie; I. Therefore, the bond between them is ionic.
Ans 42) b
Ans Desc 42) Since the electronegativity( EN) difference is 3,0-1.2=1.8, which is less than 1.9, therefore bond expected to be covalent.
Ans 43) c
Ans Desc 43)
Sulphuric Acid contains covalent and coordinate bonds. i.e.;
Ans 44) d
Ans Desc 44) Molecular solids have van der Waals forces of attraction and hence usually have low heats of fusion. i.e.; melting points
Ans 45) b
Ans Desc 45) Ethanol under-grows intermolecular H-bonding while methoxymethane does not . Hence ethanol has higher boiling point than methoxymethane.
Ans 46) a
Ans Desc 46) An element (x) of group VA (or 15) has a normal valency of three while an element (Y) of group VIA or (16) has a normal valency of 2. Therefore, the formula of the compound is X2Y3.
Ans 47) a
Ans Desc 47) The bond angle decreases progressively from H2O® H2S® H2 Se® H2Te, due to increasing bp-bp repulsion as the EN of the element decreases down the group. Thus the bond angle is maximum (104.50) for H2 O.
Ans 48) c
Ans Desc 48) contains both ionic and covalent bonds.
Ans 49) d
Ans Desc 49) CCl4 is a covalent compound , therefore, it does not give a white ppt of AgCl when treated with AgNO3 solution.
Ans 50) a
Ans Desc 50) Covalent crystals such as (SiO2, diamonds etc) are hard and have high melting points.
Ans 51) b
Ans Desc 51) According to Fajan rules, the formation of an ionic bond is favoured by low charge on ions, a large cation and a small anion.
Ans 52) b
Ans Desc 52) The removal of an electron from a diatomic molecule may increase as in the conversion of O2(2)Â® O+2(2.5) or decrease the bond order as in the conversion, . As a result, the bond energy may increase or decrease. Thus statement (b ) is incorrect.
Ans 53) b
Ans Desc 53) The removal of an electron from a diatomic molecule may increase as in the conversion of O2(2)Â® O+2(2.5) or decrease the bond order as in the conversion, . As a result, the bond energy may increase or decrease. Thus statement (b ) is incorrect.
Ans 54) b
Ans Desc 54) BH3 has sp2 hybridization and hence does not have a tetrahedral structure while all others have tetrahedral structures.
Ans 55) b
Ans Desc 55) The stability of the ionic bond depends upon the lattice energy which is expected to be more between Mg and F due to +2 charge on Mg atom.
Ans 56) b
Ans Desc 56) The angle between the bonds formed by Px, and Py orbitals is the minimum, ie. 900.
Ans 57) c
Ans Desc 57)
Ans 58) c
Ans Desc 58) The strength of the H- bond depends upon the electronegativity of the atom carrying the H- atom. Since O is more electronegative than N, therefore, H- bonding is maximum in ethanol.
Ans 59) c
Ans Desc 59) The C-C bond distance decreases as the multiplicity of the bond increases. Thus, bond distance decreases in the order: butane(1.54A0) >benzene(1.39)>ethene(1.34A0)>ethyne (1.20A0).
Ans 60) b
Ans Desc 60) In a group, electronegativity or the ionic potential decreases and hence the covalent character decreases
Ans 61) a
Ans Desc 61)
Ans 62) c
Ans Desc 62)
Ans 63) a
Ans Desc 63) Bond order cannot be negative because number of bonding electrons, is always greater than anti bonding electrons.
Ans 64) b
Ans Desc 64) O2 is paramagnetic due to the presence of two unpaired electrons.
Ans 65) b
Ans Desc 65) HCl does not have H- bonding but H-F has extensive H-bonding. Therefore the boiling point of HCl is lower than that of HF. Amongst HCl, HBr and HI, the molecular size of HCl is the smallest and has the weakest van der Waals interactions and thus has the lowest boiling point.
Ans 66) c
Ans Desc 66) O- Nitrophenol undergoes intramolecular H- bonding and hence exists as a monomer but p-nitrophenol undergoes intermolecular H-Bonding and hence exists as an associated molecule. Therefore, o-nitrophenol is more volatile than p-nitrophenol.
Ans 67) b
Ans Desc 67)
Here, Nb = 2+4+2=8 and Nb=2
Therefore Bond Order is =(8-2)/2=3.
Ans 68) b
Ans Desc 68)
Total number of electrons in CO =6+8=14
In =2´ 8+2=18
In CN–= 6+7+1 =14.
Only NO has an odd number of electrons and hence is paramagnetic.
Ans 69) a
Ans Desc 69) Both HgCl2 and CO2 are linear molecules and hence are isostructural.
Ans 70) d
Ans Desc 70) Since is divalent, therefore, the metal atom in must be trivalent. i.e.; M3+ since is also trivalent, therefore the formula of its phosphate is MPO4.
Ans 71) c
Ans Desc 71) PF5 involves sp3d hybridisation and hence has trigonal bipyramidal structure.
Ans 72) c
Ans Desc 72)
According to M O theory, the configuration of N O is .
Here Nb = 10 and Na =5 therefore B O= (10-5)/2=2.5
Ans 73) b
Ans Desc 73) According to VSEPR theory, a molecule with four bond pairs of electrons should be tetrahedral,
Ans 74) b
Ans Desc 74) only in structure (b), the octet of both N-atoms and O is complete.
Ans 75) d
Ans Desc 75) Due to the +ve charge on P, it attracts the electrons of the P-H bond towards itself. As a result it has some ionic character. In other words, the P-H bond in is least covalent.
Ans 76) b
Ans Desc 76) C2 H 4has sp2 hybridization.
Ans 77) d
Ans Desc 77) Si(CH3)4 has sp3 hybridization and is thus tetrahedral.
Ans 78) c
Ans Desc 78) are pyramidal while are planar.
Ans 79) c
Ans Desc 79) F– forms a hydrogen bond with HF, therefore the species (H….F-H)– or HF2– exists.
Ans 80) d
Ans Desc 80) Sn atom in Sn Cl2 is sp2 hybridized and hence is not linear. In fact, it has an angular shape.
Ans 81) a
Ans Desc 81) Bonding in FeCl3 is covalent.
Ans 82) d
Ans Desc 82) NH3 has high boiling point due to H-bonding.
Ans 83) b
Ans Desc 83) H bonding is possible only between N, O, and F and the H-atoms attached to these. Hence NH3 and CH4 do not form H- bonds.
Ans 84) a
Ans Desc 84) The polarizing power of a cation increases as the charge on the cation increases (Fajan rule)
Ans 85) c
Ans Desc 85) In H-O-O-H, O-H bonds are polar but O-O bond is non-polar.
Ans 86) d
Ans Desc 86) H– is the most stable since it has noble gas ie; He gas configuration.
Ans 87) d
Ans Desc 87) In He2, the anti bonding character of the two electrons in the anti bonding MO more than cancel the bonding character of the two electrons in the bonding MO and hence He2 molecule does not exist.
Ans 88) d
Ans Desc 88) Amongst the molecules listed in NH3, the electronegativity difference between N(3.0) and H(2.1) is the maximum and hence NH3has the highest dipole moment
Ans 89) d
Ans Desc 89) According to MO theory, out of a total of 16 electrons, O2 has two unpaired electrons and 14 paired electrons.
Ans 90) a
Ans Desc 90) CH4, C2 H6, and B2H6 all have symmetrical structures and hence have zero dipole moment. Only H2O2 has non-polar structure and hence has a finite dipole moment.
Ans 91) c
Ans Desc 91) The two ice cubes unite due to formation of H- bonds.
Ans 92) d
Ans Desc 92) MX4 is tetrahedral, therefore total number of angles XMX is six.
Ans 93) c
Ans Desc 93) In SnCl2 Sn has sp2 hybridization and hence has angular shape.
Ans 94) b
Ans Desc 94) Zn2+, Cd2+ all have a pseudo inert gas configuration and hence are more polarizing than Fe2+,and Mg2+ ions. Further, the smaller the cation, the greater is its polarizing power and hence the more covalent is the compound. Thus ZnCl2 has the least ionic character.
Ans 95) c
Ans Desc 95) PF5 has trigonal bipyramidal geometry. Here all the P-F bonds are not equal. Actually axial P-F bonds are longer than equatorial P -F bonds.
Ans 96) b
Ans Desc 96) Subtraction of wave functions of atomic orbitals leads to the formation of anti bonding MOs
Ans 97) b
Ans Desc 97) SO2 has sp2, has sp, has sp2n and SnCl2 has sp3 hybridization. Therefore is linear.
Ans 98) a
Ans Desc 98)
thus N2 and have identical bond order of 3.0.
Ans 99) b
Ans Desc 99)
Dipole moment of HBr when 100% if ionic =4.8´ 10-10´ 4.1´ 10-8cm
=6.678´ 10-18esu cm.
Therefore % ionic character
Ans 100) c
Ans Desc 100) Brass is a solution of solid in solid (Cu+Zn).