Chemical Bonding (13th)
Chemical Bonding (13th)
Chemical Bonding (13th)
CHEMICAL BONDING
EXERCISE I
9. Which of the following compounds contain/s both ionic and covalent bonds?
(A) NH4Cl (B) KCN (C) CuSO4·5H2O (D) NaOH
10. Among the following isostructural compounds, identify the compound, which has the highest Lattice
energy
(A) LiF (B) LiCl (C) NaCl (D) MgO
2
12. Which of the following, when dissolved in water forms a solution, which is Non-conductivity?
(A) Green Vitriol (B) Indian salt Petre
(C) Alcohol (D) Potash alum
16. Which of the following contains (electrovalent) and non-polar (covalent) bonds ?
(A) CH 4 (B) H 2 O2 (C) NH 4 Cl (D) HCN
17. A sigma bond may be formed by the overlap of 2 atomic orbitals of atoms A and B. If the bond is formed
along as the x-axis, which of the following overlaps is acceptable ?
(A) s orbital of A and p z orbital of B (B) px orbital of A and p y orbital of B
(C) p z orbital of A and p x orbital of B (D) p x orbital of A and s orbital of B
19. How many bonded electron pairs are present in IF7 molecule :
(A) 6 (B) 7 (C) 5 (D) 8
23. Rotation around the bond (between the underlined atoms) is restricted in :
(A) C 2 H 4 (B) H 2 O 2 (C) Al 2Cl 6 (D) C 2 H 6
25. Which of the following two substances are expected to be more covalent :
(A) BeCl 2 (B) SnCl 4 (C) ZnS (D) ZnCl 2
31. Which of the following molecules does not have coordinate bonds?
(A) CH3–NC (B) CO (C) O3 (D) CO 32
36. No X X bond exists in which of the following compounds having general form of X 2 H 6 ?
(A) B2 H 6 (B) C 2 H 6 (C) Al 2 H 6 (D) Si2 H 6
37. Pick out among the following species isoelectronic with CO2 :
(A) N 3 (B) (CNO) (C) (NCN ) 2 (D) NO2
42. N 2 O has a linear, unsymmetrical structure that may be thought of as a hybrid of two resonance forms. If
a resonance form must have a satisfactory Lewis structure, which of the five structures shown below are
the resonance forms of N 2 O ?
– — –
(A) N N O (B) N N O (C) N N O (D) N N O (E) N N O
1 2 3
45. In the following compound C H 2 C H C CH 2 C CH , the C 2 C3 bond is of the type :
(A) sp sp 2 (B) sp 3 sp 3 (C) sp sp 3 (D) sp 2 sp 3
46. Which of the following has a geometry different from the other three species (having the same geometry)?
(A) BF4 (B) SO42 (C) XeF4 (D) PH 4
48. Among the following species, identify the isostructural pairs : NF3 , NO3 , BF3 , H 3O , HN 3
(A) [ NF3 , NO3 ] and [ BF3 , H 3O ] (B) [ NF3 , HN 3 ] and [ NO3 , BF3 ]
(C) [ NF3 , H 3 O ] and [ NO 3 , BF3 ] (D) [ NF3 , H 3O ] and [ HN 3 , BF3 ]
49. Number and type of bonds between two carbon atoms in CaC 2 are :
(A) one sigma () and one pi () bond (B) one and two bonds
(C) one and one and a half bond (D) one bond
50. In C C bond is C 2 H 6 undergoes heterolytic fission, the hybridisation of two resulting carbon atoms is/are
(A) sp 2 both (B) sp 3 both (C) sp 2 , sp 3 (D) sp, sp 2
57. Which of the following has been arranged in increasing order of size of the hybrid orbitals ?
(A) sp sp 2 sp 3 (B) sp 3 sp 2 sp (C) sp 2 sp 3 sp (D) sp 2 sp sp 3
58. In the context of carbon, which of the following is arranged in the correct order of electronegativity :
(A) sp sp 2 sp 3 (B) sp 3 sp 2 sp (C) sp 2 sp sp 3 (D) sp 3 sp sp 2
59. When 2s 2s, 2 p 2 p and 2 p 2s orbitals overlap, the bond strength decreases in the order :
(A) p p s s p s (B) p p p s s s (C) s s p p p s (D) s s p s p p
67. The shape of a molecule which has 3 bond pairs and one lone pair is :
(A) Octahedral (B) Pyramidal (C) Triangular planar (D) Tetrahedral
71. A hydrazine molecule is split in NH 2 and NH 2 ions. Which of the following statements is/are correct ?
(A) NH 2 shows sp 2 hybridisation whereas NH 2 shows sp 3 hybridisation
(B) Al (OH ) 4 has a regular tetrahedral geometry
(C) sp 2 hybridized orbitals have equal s- and p- character
(D) Hybridized orbitals always form - bonds
74. A -bond may between two p x orbitals containing one unpaired electron each when they approach
each other appropriately along :
(A) x - axis (B) y - axis (C) z - axis (D) any direction
76. sp 3 hybridisation is in :
(A) AlH 4 (B) CH 3 (C) ClO2 (D) NH 2
84. Which of the following models best describes the bonding within a layer of the graphite structure ?
(A) metallic bonding (B) ionic bonding
(C) non-metallic covalent bonding (D) van der Waals forces
85. The critical temperature of water is higher than that of O2 because the H 2 O molecule has :
(A) fewer electrons than O2 (B) two covalent bonds
(C) V - shape (D) dipole moment
8
86. Ethanol has a higher boiling point than dimethyl ether though they have the same molecular weight. This
is due to :
(A) resonance (B) coordinate bonding (C) hydrogen bonding (D) ionic bonding
88. Which of the following compounds would have significant intermolecular hydrogen bonding ?
HF , CH 3OH , N 2O4 , CH 4
(A) HF , N 2O4 (B) HF , CH 4 , CH 3OH (C) HF , CH 3OH (D) CH 3OH , CH 4
89. For H 2O2 , H 2 S , H 2 O and HF , the correct order of increasing extent of hydrogen bonding is :
(A) H 2O HF H 2 O2 H 2 S (B) H 2 O HF H 2 S H 2 O2
(C) HF H 2 O H 2 O2 H 2 S (D) H 2O2 H 2 O HF H 2 S
90. Iron is harder than sodium because
(A) iron atoms are smaller (B) iron atoms are more closely packed
(C) metallic bonds are stronger in sodium (D) metallic bonds are stronger in iron
91. Which one of the following does not have intermolecular H-bonding?
(A) H2O (B) o-nitro phenol (C) HF (D) CH3COOH
94. Among the following, van der Waals forces are maximum in
(A) HBr (B) LiBr (C) LiCl (D) AgBr
97. The melting point of AlF3 is 104º C and that of SiF4 is - 77º C (it sublimes) because :
(A) there is a very large difference in the ionic character of the Al F and Si F bonds
(B) in AlF3 , Al 3 interacts very strongly with the neighbouring F ions to give a three dimensional
structure but in SiF4 no interaction is possible
Chemistry : Chemical Bonding 9
(C) the silicon ion in the tetrahedral SiF4 molecule is not shielded effectively from the fluoride ions
whereas in AlF3 , the Al 3 ion is shielded on all sides
(D) the attractive forces between the SiF4 molecules are strong whereas those between the AlF3 molecules
are weak
98. Two ice cubes are pressed over each other and unite to form one cube. Which force is responsible for
holding them together :
(A) van der Waal’s forces (B) Covalent attraction
(C) Hydrogen bond formation (D) Dipole-dipole attraction
102.
104. Compare O–O bond energy among O2, H2O2 and O3 with reasons.
106. Which of the following factors are responsible for van der Waals forces ?
(A) Instantaneous dipole-induced dipole interaction
(B) Dipole-induced dipole interaction and ion-induced dipole interaction
(C) Dipole-dipole interaction and ion-induced dipole interaction
(D) Small size of molecule
108. Intermolecular hydrogen bonding increases the enthalpy of vapourization of a liquid due to the:
(A) decrease in the attraction between molecules
(B) increase in the attraction between molecules
(C) decrease in the molar mass of unassociated liquid molecules
(D) increase in the effective molar mass of hydrogen - bonded molecules
10
111. In which of the following compounds, breaking of covalent bond takes place?
(A) Boiling of H2O (B) Melting of KCN (C) Boiling of CF4 (D) Melting of SiO2
112. Among KO2 , AlO2 , BaO2 and NO2 unpaired electron is present in :
(A) KO2 only (B) NO2 and BaO2 (C) KO2 and AlO2 (D) BaO2 only
114. In which of the following sovents, KI has highest solubility? The dielectric constant () of each liquid is
given in parentheses.
(A) C6H6(= 0) (B) (CH3)2CO (=2) (C) CH3OH (=32) (D) CCl4(=0)
117. For which of the following crystalline substances does the solubility in water increase upto 32º C and
then decrease rapidly ?
(A) CaCl2 .2H 2O (B) Na 2SO 4 .10H 2O (C) FeSO4 .7 H 2O (D) Alums
118. Which of the following has been arranged in order of decreasing dipole moment ?
(A) CH 3Cl CH 3 F CH 3 Br CH 3 I (B) CH 3 F CH 3Cl CH 3 Br CH 3 I
(C) CH 3Cl CH 3 Br CH 3 I CH 3 F (D) CH 3 F CH 3Cl CH 3 I CH 3 Br
120. The experimental value of the dipole moment of HCl is 1.03 D. The length of the H Cl bond is
1.275 Å . The percentage of ionic character in HCl is :
(A) 43 (B) 21 (C) 17 (D) 7
Cl
129. Which of the following has been arranged in order of decreasing bond length ?
(A) P O Cl O S O (B) P O S O Cl O
(C) S O Cl O P O (D) Cl O S O P O
130. If a molecule MX 3 has zero dipole moment, the sigma bonding orbitals used by M (atm. no. < 21) are :
(A) pure p (B) sp hybrid (C) sp 2 hybrid (D) sp 3 hybrid
132. Among the following species, which has the minimum bond length ?
(A) B2 (B) C 2 (C) F2 (D) O2
135. H B H bond angle in BH 4 is :
(A) 180º (B) 120º (C) 109º (D) 90º
136. In the series ethane, ethylene and acetylene, the C H bond energy is :
(A) The same in all the three compounds (B) Greatest in ethane
(C) Greatest in ethylene (D) Greatest in acetylene
137. Which one of the following compounds has bond angle as nearly 90º ?
(A) NH 3 (B) H 2 S (C) H 2 O (D) SF6
138. State whether each statement is true or false. If false, write the correct statement.
(i) The polarising power of a cation is directly proportional to its charge.
(ii) The polarising power of a cation is directly proportional to its size.
(iii) The polarisability of an anion is directly proportional to its charge.
(iv) The polarisability of an anion is directly proportional to its size.
(v) For a given anion, greater the polarising power of the cation, more the ionic character.
(vi) For a given cation, greater the polarisability of the anion, more the covalent character.
(vii) An element with low ionization potential is most likely to form a covalent bond with an other
element having a high electron affinity.
(viii) Ionic interactions are stronger than covalent bonds.
(ix) Two non-metal atoms are likely to form covalent bonds on combination.
(x) Ionic interactions are directional.
141. AgNO3 gives a white precipitate with NaCl but not with CCl 4 . Why ?
Chemistry : Chemical Bonding 13
142. Using VSEPR theory identify the type of hybridisation and draw the structure of OF2 .
143. What should be the structure of the following as per VSEPR theory ?
(a) XeF2 (b) XeF4 (c) PBr5 (d) OF2 (e) I 3 and (f) I 3
144. The percent ionic character in HCl is 18.08. The observed dipole moment is 1.08 D. Find the inter-nuclear
distance in HCl.
145. In the hydrides of group VI elements the central atoms involve sp 3 hybridisation but the bond angles
decrease in the order, H 2 O, H 2 S , H 2 Si , H 2Te . How would you account for this ?
146. Assuming that all the four valency of carbon atom in propane pointing towards the corners of a regular
tetrahedron. Calculate the distance between the terminal carbon atoms in propane. Given, C C single
bond length is 1.54 Å.
147. The dipole moment of HBr is 7.95 debye and the intermolecular separation is 1.94 10 10 m Find the %
ionic character in HBr molecule.
148. HBr has dipole moment 2 . 6 10 30 cm . If the ionic character of the bond is 11.5 %, calculate the
interatomic spacing.
149. Dipole moment of LiF was experimentally determined and was found to be 6.32 D. Calculate percentage
ionic character in LiF molecule Li F bond length is 0.156 pm.
150. A diatomic molecule has a dipole moment of 1.2 D. If bond length is 1.0 Å, what percentage of an
electronic charge exists on each atom.
14
EXERCISE - II
(A) sp2 & sp2 (B) sp3 & sp (C) sp & sp2 (D) sp & sp
3. The species which the central atom uses sp2 hybrid orbitals in its bonding is [ JEE '88]
(A) PH3 (B) NH3 (C) CH3+ (D) SbH3
*
8. The compound in which C uses its sp3 hybrid orbitals for bond formation is : [ JEE '89]
* * *
(A) H C* OOH (B) ( H 2 N ) C O (C) (CH 3 ) 3 C OH (D) CH 3 C HO
10. Which one of the following is the smallest in size [ JEE '89]
(A) N 3 (B) O 2 (C) F (D) Na +
11. The number of sigma and pi bonds in 1-butene-3-yne are [ JEE '89]
(A) 5 sigma 5 pi (B) 7 sigma 3 pi (C) 8 sigma 2 pi (D) 6 sigma 4 pi
12. Amongst the following the one having highest I.E. is [ JEE '90]
(A) [Ne] 3 s2 3 p1 (B) [Ne] 3 s2 3 p3 (C) [Ne] 3 s2 3 p2 (D) [Ar] 3 d° 4 s2 4 p3
14. The type of hybrid orbitals used by the chlorine atom in ClO2- is [ JEE '92]
(A) sp3 (B) sp2 (C) sp (D) none
Chemistry : Chemical Bonding 15
15. The CN - & N2 are isoelectronic. But in contrast to CN - , N2 is chemically inert because of
(A) Low bond energy [ JEE '92]
(B) Absence of bond polarity
(C) Unsymmetrical electron distribution
(D) Presence of more number of electron in bonding orbitals.
16. The maximum possible number of hydrogen bonds a water molecule can form is [ JEE '92]
(A) 2 (B) 4 (C) 3 (D) 1
17. Pick out the isoelectronic structures from the following [ JEE '93]
I. CH3+ II. H3O+ III. NH3 IV. CH3-
(A) I and II (B) III and IV (C) I and III (D) II, III and IV
18. The number of electrons that are paired in oxygen molecule is [ JEE '95]
(A) 7 (B) 8 (C) 16 (D) 14
20. The order of increasing thermal stabilities of K2CO3(I) , MgCO3(II) , CaCO3(III) , BaCO3(IV) is
[ JEE '96]
(A) II < III < IV < I (B) IV < II < III < I (C) IV < II < I < III (D) II < IV < III < I
21. Identify isostructural pairs from NF3(I) , NO3-(II) , BF3(III) , H3O+(IV), HN3(V) [ JEE '96]
(A) I & II, III & IV (B) I & V, II & III (C) I & IV, II & III (D) I & IV, III & V
22. (i)The number and type of bonds between two C - atom in CaC2 are [ JEE '96]
(A) 1 sigma 1 pi (B) 1 sigma 2 pi (C) 1 sigma , ½ pi (D) 1 sigma
24. Among KO2 , AlO2- , BaO2 & NO2+ unpaired electron is present in [ JEE '97]
+
(A) NO2 & BaO2 (B) KO2 & AlO2 - (C) KO2 only (D) BaO2 only
25. Which of the following has maximum number of unpaired electrons? [ JEE '96]
(A) Mg2+ (B) Ti3+ (C) V3+ (D) Fe2+
26. KF combines with HF to form KHF2. The compound contains the species [ JEE '97]
+ -
(A) K , F and H+ + -
(B) K , F and HF +
(C) K and [HF2] - (D) [KHF] and F-
+
27. Among the following compounds the one that is polar and has the central atom with sp2
hybridisation is [ JEE '97]
(A) H2CO3 (B) SiF4 (C) BF3 (D) HClO2
28. Which contains both polar & non polar covalent bonds [ JEE '97]
(A) NH4Cl (B) HCN (C) H2O2 (D) CH4
16
29. The type of hybrid orbitals used by the chlorine atom in ClO3- is [ JEE '97]
(A) sp3 (B) sp3d (C) sp3d2 (D) sp2
31. What type of hybridisation and how many lone pair of electrons are present in the species I3- on the
central atom. [ JEE '97]
2 3
(A) sp one lone pair (B) sp d three lone pair (C) sp three lone pair (D) sp no lone pair
32. In which of the following the central atom does not use sp3 hybrid orbitals in its bonding?
(A) BeF3- (B) OH3+ (C) NH2- (D) NF3 [ JEE '97]
34. The maximum angle around the central atom H-M-H is present in
(A) AsH3 (B) PH3 (C) NH3 (D) SbH3
37. The geometry & the type of hybrid orbitals present about the central atom in BF3 is : [ JEE '98]
(A) linear, sp (B) trigonal planar, sp2 (C) tetrahedra sp3 (D) pyramidal, sp3
38. The correct order of increasing C - O bond length of, CO, CO32- , CO2 is [ JEE '99]
(A) CO32- < CO2 < CO (B) CO2 < CO32- < CO
(C) CO < CO32- < CO2 (D) CO < CO2 < CO32-
40. The geometry of H2S and its dipole moment are [ JEE '99]
(A) angular & non zero (B) angular & zero
(C) linear & non zero (D) linear & zero
41. In compounds type E Cl3, where E = B, P, As or Bi, the angles Cl - E - Cl for different E are in the order
(A) B > P = As = Bi (B) B > P > As > Bi (C) B < P = As = Bi (D) B < P < As < Bi
[ JEE '99]
42. The most unlikely representation of resonance structure of p–nitrophenoxide is:
43. Amongst H2O, H2S , H2Se and H2Te, the one with the highest boiling point is [JEE 2000]
(A) H2O because of hydrogen bonding (B) H2Te because of higher molecular weight
(C) H2S because of hydrogen bonding (D) H2Se because of lower molecular weight
44. The hybridization of atomic orbitals of nitrogen in NO 2 , NO 3 and NH 4 are [JEE 2000]
(A) sp2, sp3 and sp2 respectively (B) sp, sp2 and sp3 respectively
(C) sp2, sp and sp3 respectively (D) sp2, sp3 and sp respectively
45. Specify the coordination geometry around and hybridization of N and B atoms in a 1 : 1 complex of BF3
and NH3 [JEE 2002]
(A) N : tetrahedral, sp3 ; B : tetrahedral, sp3 (B) N : pyramidal, sp3; B : pyramidal, sp3
(C) N : pyramidal, sp3 ; B : planar, sp2 (D) N : pyramidal, sp3; B : tetrahedral, sp3
46. The nodal plane in the -bond of ethene is located in [JEE 2002]
(A) the molecular plane
(B) a plane parallel to the molecular plane
(C) a plane perpendicular to the molecular plane which bisects, the carbon-carbon bond at right angle.
(D) a plane perpendicular to the molecular plane which contains, the carbon-carbon bond.
47. Which of the following molecular species has unpaired electron(s)? [JEE 2002]
(A) N2 (B) F2 (C) O 2 (D) O 22
48. Which of the following are isoelectronic and isostructural ? NO 3 , CO 32 , ClO 3 , SO3 [JEE 2003]
(A) NO 3 , CO 32 (B) SO3, NO3 (C) ClO 3 , CO 32 (D) CO32 , SO3
49. Which species has the maximum number of lone pair of electrons on the central atom? [JEE 2005]
(A) ClO3– (B) XeF4 (C) SF4 (D) I3–
6. The experimentally determined N - F bond length in NF3 is greater than the sum of single bond
covalent radii of N & F . Explain. [ JEE '95]
7. Explain the difference in the nature of bonding in LiF & LiI. [ JEE '96]
8. Explain PCl5 is formed but NCl5 cannot. [JEE '97]
9. Give reasons for the following in one or two sentences only. [ JEE '99]
(a) BeCl2 can be easily hydrolyed (b) CrO3 is an acid anhydride .
10. Explain why o-hydroxybenzaldehyde is a liquid at room temperature, while p-hydroxybenzaldehyde is a
high melting solid. [ JEE '99]
Chemistry : Chemical Bonding 19
Miscellaneous.
1. Write two resonance structures of ozone which satisfy the octet rule. [JEE '91]
2. Using VSEPR theory , identify the type of hybridisation & draw the structure of OF2. What are
oxidation states of O & F. [JEE '94]
3. What are the types of bond present in B2H6? [IIT 1994]
4. Arrange toluene, m–dichlorobenzene, o–dicholorobenzene and p–dichlorobenzene in order of increasing
dipole moment. [IIT 1996]
5. Draw the structures of [JEE '97]
(i) XeF2 (ii) XeO3 (iii) XeF4 (iv) BrF5 (v) SO3 2-
6. Interpret the non-linear shape of H2S molecule & non planar shape of PCl3 using VSEPR theory.
[JEE '98]
7. Discuss the hybridisation of C - atoms in allene (C3H4) and show the orbital overlaps.[JEE '99]
8. Using VSEPR theory, draw the shape of PCl5 and BrF5. [JEE 2003]
9. Draw the structure of XeF4 and OSF4 according to VSEPR theory, clearly indicating the state of
hybridisation of the central atom and lone pair of electrons (if any) on the central atom. [JEE 2004]
20
ANSWER KEY
EXERCISE - I
1. C 2. B 3. A 4. C 5. D
6. B 7. D 8. A,B,C,D 9. A,B,C,D 10. D
11. A 12. C 13. B,C,D 14. C 15. A,C
16. C 17. D 18. D 19. B 20. A
21. D 22. A,B 23. A,C 24. B,C 25. A,B
26. A,B,C 27. B 28. D 29. C 30.
B,C,D
31. D 32. A 33. D 34. D 35 C
36. A,C 37. A,B,C 38. A,B 39. B,C,D 40.
B,C,D
41. A,B,C,D 42. A,E 43. A,C 44. A 45. D
46. C 47. B 48. C 49. B 50. C
51. A 52. C 53. C 54. D 55. B
56. A 57. A 58. A 59. B 60. A
61. C 62. C 63. B 64. C 65. C
66. A 67. B 68. D 69. A 70.
A,C,D
71. A,B,D 72. B,D 73. A,B 74. A 75. A,B
76. A,B,C,D 77. B 78. A,B,D 79. A,B 80. B,C
81. A,D 82. A,B,C 83. C 84. C 85. D
86. C 87. D 88. C 89. C 90. D
91. B 92. B 93. C 94. D 95. C
96. D 97. B 98. C 99. A 100. A
101. B 102. B,C,D 103. B,D 104. O2 >O3 >H2O2.
105. A,D 106. A,B,C 107. A,B 108. B
109. A,B,C,D 110. A,B,C,D 111. D 112. A 113. A
114. C 115. D 116. D 117. B 118. A
119. B 120. C 121. A 122. D 123.
A,C,D
124. B,C,D 125. B,C,D 126. A,B,C,D 127. B 128. A
129. B 130. C 131. A 132. B 133. B
134. A 135. C 136. D 137. B,D
138. T, F, T, T, F, F, F, T, T, F 139. F, F, F, F, T, T, F, F
140. (i) p-orbital, (ii) –bond, (iii) 1 , (iv) LP–LP & LP–BP, (v) more, less, (vi) 36
143. (a) Linear, (b) square planar, (c) T.B.P. (d) bent, (e) linear, (f) bent
144. 1.2Å 146. 2.33 Å 147. 85% 148. 1.4 Å
149. 84.5% 150. 25%
.
EXERCISE - II
1. C 2. A 3. C 4. A 5. B 6. A 7. A
8. C 9. C 10. D 11. B 12. B 13. C 14. A
15. B 16. B 17. D 18. D 19. A 21. C 22. B
23. C 24. C 25. D 26. C 27. A 28. A 29. A
30. B 31. B 32. A 33. B 34. C 35. D 36. B
37. B 38. D 39. B 40. A 41. B 42. C 43. A
44. B 45. A 46. A 47. C 48. A 49. D
Chemistry : Chemical Bonding 21
Miscellaneous.
1. or
5. (i) Linear, (ii) Pyramidal, (iii) Square planar, (iv) Square pyramidal, (v) pyramidal
7. CH 3 C CH 3
2
sp sp sp 2