Chemical Bonding Exercise # 2

CHEMICAL BONDING Exercise # 2 Part # I [Multiple Correct Choice Type Questions] 1. Most ionic compounds have : (A) high melting points and low boiling points (B) high melting points and non-directional bonds (C) high solubilities in polar solvents and low solubilities in nonpolar solvents (D) three-dimensional crystal structures, and are good conductors of electricity in the molten state. 2. All bond : (A) dissociations are exothermic (C) enthalpies are positive 3. (B) dissociations are endothermic (D) enthalpies are negative Which of the following compounds contain(s) both ionic and covalent bonds? (A) NH4Cl (B) KCN (C) CuSO4·5H2O (D) NaOH 4. Which of the following statements concerning the molecule H – C  C – CH3 is / are not correct. (A) It has 6 and 2 bonds (B) Both the -bonds are present in the same plane (C) The central carbon atom is sp hybridised while the terminal atoms are sp 2 hybridised (D) The molecule is linear 5. In which of following, vacant orbital take part in hybridisation : (A) BF3 6. (B) PCl6– (C) BF4–  H (D) N 3 Which is not true about VSEPR theory (A) Lone pair-lone pair repulsion is maximum. (B) Lone pair and double bond occupy axial position in trigonal bipyramidal structure. (C) More electronegative atoms occupies axial position in trigonal bipyramidal structure. (D) Bigger atoms occupy axial positions in trigonal bipyramidal structure. 7. Select the correct statement. (A) Perxenate ion is [XeO6]4– with octahedral geometry. (B) XeF2 is linear molecule with 3 lone pairs (l.p) (C) XeOF4, XeF4, XeO2F2 all contains one lone pair only (D) None of these 8. Which is/are in linear shape ? (A) NO2+ (B) XeF2 (C) 3– Which is true about NH2–, NH3 ,NH4+ ? (A) Hybridization of N is same. (C) Molecular geometry (i.e. shape) is different. (B) No. of lone pair of electron on N are same. (D) Bond angle is same. 9. (D) 3+ 10. Identify the correct option(s) (A) NH4+ > NH3 > NH2– order of bond angle (B) (CH3)3 B is a trigonal planar molecule (not considering the H-atoms on ‘C’) (C) In NH4Cl ‘N’ atom is in sp3d hybridisation (D) In S8 molecule a total of 16 electrons are left on all the ‘S’ atoms after bonding . 11. Which of the following molecule (s) has/have bond angle close to 90º ? (A) NH3 (B) H2S (C) PH3 (D) ICl3 12. Which of the following Lewis diagram is/are incorrect ? +     (A) Na  O C l  13. 14. – (B) H   H H | | |   (C)  H – N – H  [:S]2– (D) H  N  N  H   |   H   2 Hypervalent compound is(are) : (A) SO32 (B) PO43 Which are the exceptions of the lewis octet rule (A) NO3– and N2O (B) BeH2 and NO (D) CIO4 (C) SO42 (C) KrF2 and ClF3 (D) All of these 15. Which of the following overlaps is/are incorrect [assuming X-axis to be the internuclear axis] : (a) 2py + 2py   (b) 2pz + 2pz   (c) 2px + 2px   (d) 1s + 2py   (e) 2py + 2pz   (f) 1s + 2s   (A) ‘a’ & ‘b’ (B) ‘b’ & ‘d’ (C) ‘d’ & ‘f’ (D) ‘c’ & ‘e’ 16. In which of the following molecule bonding is taking place in excited state (A) CH4 (B) BF3 (C) Cl3 (D) PCl3 17. Which statement is correct about hybridization ? (A) In hybridisation orbitals take part (B) In hybridisation electrons take part (C) In hybridisation fully filled , half filled or empty orbitals can take part (D) Hybridised orbitals only contains bond pair electron 18. Which of the following represent the given mode of hybridisation sp 2 – sp2 – sp – sp from left to right (A) H2C = C = C = CH2 (B) HC  C – C  CH (C) H2C = CH – C  N (D) H2C = CH – C  CH 19. Which of the following is/are electron deficient compounds ? (A) NaBH4 (B) B2H6 (C) AlCl3 (D) LiAlH4 20. Which of the following statements is/are correct ? (A) Out of trimethylamine and trimethylphosphine, trimethylamine has higher dipole moment. (B) Out of (SiH3)2O and (CH3)2O, (SiH3)2O is more basic. (C) C – C bond length (in pm) in C2 molecule is greater than O – O bond length in O2 molecule. (D) N(SiMe3)3 and BF3 molecules are isostructural. 21. The species which are paramagnetic is/are : (A) NO (B) NO2 22. 23. 24. (C) ClO2 (D) N2O4 Which of the following reactions is/are likely to be impossible. (A) (CH3)2O + BF3  (B) (SiH3)2O + BF3  (C) (SiH3)3N + BF3  (D) All the above Which of the following have bond order three ? (A) O22+ (B) NO+ (D) CN+ (C) CN– Which of the statement(s) are correct ? (A) There is a single bond in FO+ (B) The F and O are further apart in FO– than in FO+. (C) There is a double bond in FO–. (D) It would take more energy to break F – O bond in FO+ than in FO–. CHEMICAL BONDING 25. Which of the following statements is incorrect about P4O10 molecule ? (A) Each ‘P’ atom can be considered to be sp3 hybridised (B) There are six POP bonds in the molecule (C) There are two types of P— O bond lengths  (D) POP angle is 180°. 26. Which of the following statements is /are true for P4S3 molecule ? (A) It contains six P–S bonds and three P–P bonds. (B) It contains six P–S bonds and ten lone pairs. (C) It has all atoms sp3 hybridised. (D) It contains six P–P bonds and ten lone pairs. 27. Identify the correct statement (s) (A) in H-atom bond is formed by non direction orbital (B) graphite behaves as conductor as well as semi conductor. (C) in SiO2 molecule Si-atom is sp3 hybridised (D) ClF3 is hyper valent molecule. 28. Which of the following statements is /are true about the structure of fullerene (Buckminister fullerene) ? (A) All the carbon atoms undergo sp2 hybridisation. (B) Remaining fourth electron at each carbon is delocalised in molecular orbitals which in turn gives aromatic character to molecule. (C) It has a shape like rugby ball. (D) It contains both single and double bonds and has two C–C distances of 143.5 pm and 138.3 pm respectively. 29. 30. Identify the correct statement (A) H2S2O7 has peroxy linkage (C) H2S2O8 has peroxy linkage (B) H2S2O6 has S–S linkage (D) H2SO3(Sulphurous acid) has S in +4 oxidation state Identify correct order of bond angles (A) Cl2O > F2O and F2O < H2O (B) AsI3 > AsBr3 > AsCl3 (C) NO2+ > NO2– (D) Hb B̂ Hb > Ht B̂ Ht ; where Ht is terminal Hydrogen of B2H6 and Hb is the bridging Hydrogen of B2H6 31. Choose the correct options. (A) In N2 H4, the N–N, bond length is greater than expected value. (B) In trisilyl amine (SiH3)3 N, the Si–N bond length is lesser than expected value. (C) The bond angle in OF2 is lesser than OCl2. (D) The Be atom in BeCl2(s) is sp3 hybridised. 32. In the following, identify the incorrect statements. (A) N2F3+ is a planar at each nitrogen atom (B) In F2 molecule, the energy of  2pz is more than 2px and 2py. (C) The O–O bond length in H2O2 is smaller than in O2F2 . (D) B2, O2 and F2 are paramagnetic molecules. 33. Among the following, the species with one unpaired electron are : (A) O2+ (B) NO (C) O2– (D) B2 34. Which of the following factors do not favour electrovalency ? (A) Low charge on ions (B) High charge on ions (C) Large cation and small anion (D) Small cation and large anion 35. Which statement(s) is/are correct ? (A) Polarising power refers to cation. (B) Polarisability refers to anion. (C) Small cation is more efficient to polarise anion. (D) Molecules in which cation having pseudo inert gas configuration are more covalent. 36. Which of the following is/are correct statement(s). (A) Increasing covalent character : NaCl < MgCl2 < AlCl3 (B) Increasing covalent character : LiF < LiCl < LiBr < LiI. (C) Increasing polarizability : F– < Cl– < Br – < I– (D) Decreasing ionic nature : MCl3 > MCl2 > MCl 37. Which of the following statements is / are true for the metallic bond ? (A) It is an electrical attraction between delocalised electrons and the positive part of the atom. (B) Transition metals may use inner d– electrons along with the outer s–electrons for metallic bonding. (C) Strength of metallic bond does not depend on the type of hybrid orbitals participating in metallic bonding. (D) Strength of metallic bond is inversely proportional to the radius of metallic atom. 38. Which of the following statements are correct ? (A) PbI2 is yellow due to high polarization of Pb2+ (B) Beryllium chloride exists in a polymeric chain like structure in solid state. (C) The thermal stability of alkalline earth metal carbonates follow the order : BeCO3 < MgCO3 < CaCO3 < SrCO3 < BaCO3 (D) Cu has higher covalent character than Na. 39. The halogen form compounds among themselves with formula XX, XX3, XX5 and XX7 where X is the heavier halogen. Which of the following pairs representing their structures and being polar and non-polar are correct? (A) XX – Linear – polar (B) XX3 – T-shaped – polar (C) XX5 – square pyramidal – polar (D) XX7 – Pentagonal bipyramidal – non-polar 40. Which of the following is/are correct statement(s) for dipole moment ? (A) Lone pair of electrons present on central atom can give rise to dipole moment. (B) Dipole moment is vector quantity. (C) CO2 molecule has dipole moment. (D) Difference in electronegativities of combining atoms can lead to dipole moment. 41. Which of the following molecules have intermolecular hydrogen bonds ? (A) KH2PO4 (B) H3BO3 (C) C6H2CO2H (D) CH3OH 42. Which is correct statement : (A) Borazine has higher intermolecular force of attraction as compared to benzene. (B) Ka2 fumaric acid is more than Ka2 of maleic acid due to intra molecular hydrogen bonding in maleic acid. (C) The O – O bond length in O2[AsF4] is shorter then KO2. (D) The bond angle order in halogen – S – halogen is OSF2 < OSCl2 < OSBr2 CHEMICAL BONDING 43. Select the correct statement(s). (A) Br2 and ICl have the same number of electrons and thus both have nearly the same boiling points. (B) N2H4 is pyramidal about each N-atom. (C) In P4S3 molecule, there are six P-S bonds, three P-P bonds and ten lone pairs of electrons (on all atoms). (D) In ClO4–, all Cl – O bonds are identical and there is strong p – d bonding between chlorine and oxygen atoms. 44. Which of following is correct (A) PH3 < AsH3 < SbH3 < NH3 (B) D2O(s) > H2O (l) (C) Mn > Ca > Sr > Rb (D) H2 < CO2 < H2O order of boiling point order of density order of metallic bond strength increasing order of intermolecular forces of attraction 45. Which of the following statements is/are correct : (A) Individual oxidation number of two sulphur atoms in thiosulphate (S2O32–) ion are +4 and 0, however the average oxidation number of sulphur is +2. (B) The reason for Ka2 <<< Ka1 for peroxymonosulphuric acid is, intramolecular H–bonding in the anion of acid after first ionisation. (C) NH3 has a higher boiling point than SbH3, because of H–bonding between NH3 molecules. (D) Among HCl, HBr and HI, HI is the strongest acid while HCl is the weakest acid while among HOCl, HOBr and HOI, HOCl is the strongest acid while HOI is the weakest acid. 46. Which of the following statements is correct regarding phosphoric acid ? (A) p–d back bonding exist between O and P (B) The anion is resonance stablized (C) It is a dibasic acid (D) Inter molecular H bonding between molecules make it a syrupy (viscous) liquid. 47. The critical temperature of water is higher than that of O2 because the H2O molecule has : (A) fewer electrons than O2 (B) two covalent bonds (C) V - shape (D) dipole moment 48. Which of the following are polar ? (A) XeF4 (B) XeF6 (C) XeOF4 (D) XeF5– 49. Which of the following statement(s) is/are correct? (A) Ethyne gas is more soluble in acetone than in water. (B) CH3F is more polar than CD3F due to deuterium (D) being less electronegative than hydrogen (H). (C) Silyl isocyanate (SiH3NCO) is linear in shape while methyl isocyanate (CH3NCO) is bent in shape. (D) All of these 50. In which of the following compounds B atoms are in sp2 and sp3 hybridisation states ? (A) Borax (B) Diborane (C) Borazole (D) All 51. (a) There are only 12 bonding electrons available in one molecule of diborane. (b) B3N3H6 is an electron deficient compound. (c) Al2Cl6 sublimes on heating and give AlCl3 vapours at high temperature. (d) In Si2O76– anion, one oxygen of a SiO44– tetrahedron is shared with another SiO44– tetrahedron. (A) T F T T (B) F T F F (C) T F T F (D) F T F T 52. 53. 54. The correct order of decreasing polarizability of ion is : (A) Cl , Br  ,   , F  (B) F  ,   , Br  , Cl (C)   , Br  , Cl , F  (D) F  , Cl , Br  ,   Which of the following is in order of increasing covalent character ? (A) CCl 4  BeCl 2  BCl 3  LiCl (B) LiCl  CCl4  BeCl2  BCl3 (C) LiCl  BeCl 2  BCl3  CCl4 (D) LiCl  BeCl 2  CCl4  BCl3 Which of the following combination of ion will have highest polarisation ? (A) Fe2+, Br– (B) Ni4+, Br– (C) Ni2+, Br– 55. SnCl4 is a covalent liquid because : (A) electron clouds of the Cl– ions are weakly polarized to envelop the cation. (B) electron clouds of the Cl– ions are strongly polarized to envelop the cation. (C) its molecules are attracted to one another by strong van der Waals forces. (D) Sn shows inert pair effect. 56. Which of the following has highest melting point according to Fajan's rule : (A) NaCl (B) MgCl2 (C) AlCl3 57. 58. 59. 60. 61. Iron is harder than sodium because : (A) iron atoms are smaller. (C) metallic bonds are stronger in sodium. (D) Fe, Br– (D) LiCl (B) iron atoms are more closely packed. (D) metallic bonds are stronger in iron. The enhanced force of cohesion in metals is due to (A) The covalent linkages between atoms (B) The electrovalent linkages between atoms (C) The lack of exchange of valency electrons (D) The delocalization of valence electron between metallic kernels. In the following metals which one has lowest probable interatomic forces (A) Copper (B) Silver (C) Zinc (D) Mercury Which of the following cannot be explained on the basis of Fajan’s Rules ? (A) Ag2S is much less soluble than Ag2O (B) Fe(OH)3 is much less soluble than Fe(OH)2 (C) BaCO3 is much less soluble than MgCO3 (D) Melting point of AlCl3 is much less than that of NaCl The correct order of the increasing ionic character is : (A) BeCl2 < MgCl2 < CaCl2 < BaCl2 (B) BeCl2 < MgCl2 < BaCl2 < CaCl2 (C) BeCl2 < BaCl2 < MgCl2 < CaCl2 (D) BaCl2 < MgCl2 < CaCl2 < BeCl2 62. Which of the following compounds of elements in group IV is expected to be most ionic ? 63. (A) PbCl2 (B) PbCl4 Least melting point is shown by the compound : (C) CCl4 (D) SiCl4 (A) PbCl2 (C) NaCl (D) AlCl3 64. (B) SnCl4 Which of the following is observed in metallic bonds ? (A) Mobile valence electrons (B) Localised electrons (C) Highly directed bond (D) None of these CHEMICAL BONDING 65. S1 : AgI is less soluble in water than AgF due to more polarisation of I- in comparison to F– ion. S2 : Melting point of BaCl2 is higher than the melting point of BeCl2 due to greater ionic nature of BaCl2. S3 : Order of hydrated radii is : Al3+ (aq) > Mg2+ (aq) > Na+ (aq) (A) T T T (B) T T F (C) T F T (D) F T T 66. CuI2 is unstable even at ordinary temperature because : (A) the Cu2+ ion with a comparatively small radius has a strong polarising power. (B) the Cu2+ ion with a 17 electron outer shell has weak polarising power. (C) the I– ion with a larger radius has a high polarisability. (D) both (A) and (C) 67. Which of the following statements is incorrect ? (A) N2 and C2 molecules contain both  and  bonds. (B) Cu2+ is more stable than Cu+ in aqueous medium. (C) The electrical conductivity of metals can not be explained by electron sea model. (D) (A) and (C) both 68. Which anion has the highest polarisability? (A) I– 69. 70. (B) Cl– Boron forms covalent compound due to (A) Small size (C) Lower ionization energy (C) F– (D) Br– (B) Higher ionization energy (D) Both (A) and (B) Which has maximum dipole moment ? (A) (B) (C) (D) 71. Which of the following compounds possesses zero dipole moment? (A) Benzene (C6H6) (B) Carbon tetrachloride (C) Boron trifluoride (D) All of these 72. Of the following molecules, the one, which has permanent dipole moment, is : (A) SiF4 (B) BF3 (C) PF3 (D) PF5 Which of the following has the least dipole moment ? (A) NF3 (B) CO2 (C) SO2 (D) NH3 73. 74. The geometry of H2S and its dipole moment are : (A) angular and non zero (C) linear and non zero [JEE–1999, 2/80] (B) angular and zero (D) linear and zero 75. Which of the following statements is false for XeO3F2 ? (A) Hybridisation of central atom xenon is sp3d. (B) The compound is non-polar. (C) The compound has p-d bonding. (D) None. 76. The gaseous HX molecule has a measured dipole moment of 4.0 D, which indicates that it is a very polar molecule. The separation between the nuclei in this molecule is 2.67 × 10–8 cm then the percentage ionic character in HX molecule is : (A) 78% (B) 31.25% (C) 50.25% (D) None of these 77. Which of the following has been arranged in order of decreasing dipole moment ? (A) CH 3 Cl > CH 3 F > CH 3 Br > CH 3 I (B) CH 3 F > CH 3Cl > CH 3 Br > CH 3 I (C) CH 3 Cl > CH 3 Br > CH 3 I > CH 3 F (D) CH 3 F > CH 3Cl > CH 3 I > CH 3 Br 78. The dipole moment of chlorobenzene is 1.73 D. The dipole moment of p-dichlorobenzene is expected to be : (A) 3.46 D (B) 0.00D (C) 1.73 D (D) 1.00 D 79. 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 80. Consider the following sets of H-bonds P: –O–H----- Q: –O–H ----- R: – S: H----- The correct order of H-bond strengths is : (A) Q > P > S > R (C) R > S > P > Q 81. H----- (B) R > Q > S > P (D) P > Q > R > S Which of the following compounds would have significant intermolecular hydrogen bonding ? HF, CH3OH, N2O4, CH4 (A) HF, N2O4 (B) HF, CH4, CH3OH (C) HF, CH3OH (D) CH3OH, CH4 82. Which of the following is not correctly matched with respect to the intermolecular forces existing amongst the molecules (Hydrogen bonding is not taken as dipole-dipole attraction) ? (A) Benzene – London dispresion forces (B) Orthophosphoric acid – London dispresion force, hydrogen bonding. (C) Hydrochloric acid – London dispresion force, dipole-dipole attraction (D) Iodine monochloride – London dispersion force 83. Which of the following factor is 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) All of these. 84. Which of the following bonds/forces is weakest ? (A) Covalent bond (B) Ionic bond (C) Hydrogen bond (D) London force 85. In which of the following compound, intra–molecular H–bonding is not observed : (A) O–hydroxy benzyaldehyde (B) O–nitrophenol (C) Chloral hydrate (D) Boric acid 86. Which of the following statement is not true ? (A) CCl4 has higher boling point that CHCl3. (B) The HF2 – ion exists in the solid state and in liquid HF solution , but not in dilute aqueous solutions. (C) Hydrogen bonding maintains the planar H3BO3 units in layers in solid state. (D) None of these. CHEMICAL BONDING 87. Which is correct about D2O (A) Its boiling point is higher than that of H2O (l) (B) O – D - - - - O bond is stronger than O – H - - - - O bond. (C) D2O(s) sinks in H2O (l). (D) all the above are correct. 88. Amongst NH3, PH3, AsH3 and SbH3 the one with highest boiling point is : (A) NH3 because of lower molecular weight (B) SbH3 because of higher molecular weight (C) PH3 because of H-bonding (D) AsH3 because of lower molecular weight 89. S1 : In the solid B(OH)3 units are hydrogen bonded together into two-dimensional sheets with almost hexagonal symmetry. S2 : Na2CO3 can be isomorphous with Na2SO3 as both have similar formula type. S3 : XeO3F2 has one lone pair of electron on central xenon atom. S4 : D2O has higher boiling point than H2O (A) T F T F (B) T F F T (C) T T F F (D) T T T T 90. The correct order of boiling point is : (A) H2O < H2S < H2Se < H2Te (C) H2O > H2S > H2Se > H2Te 91. (B) H2O > H2Se > H2Te > H2S (D) H2O > H2Te > H2Se > H2S Which of the following compounds has the highest boiling point (A) HCl (B) HBr (C) H2SO 4 (D) HNO3 92. If molecule MX3 has Zero dipole moment, the hybrid orbitals used by M (Atomic No. < 21) are (A) Pure p (B) sp hybrid (C) sp2 hybrid (D) sp3 hybrid 93. Which of the following would be expected to have a dipole moment of zero on the basis of symmetry? (A) SOCl2 (B) OF2 (C) SeF6 (D) ClF5 94. Among the XeF2, SF2Cl2, XeOF2 , ICl2– , IOCl4– and F2ClO+1 S1 : XeF2, ICl2– , XeOF2 have zero dipole moment S2 : IOCl4– and F2ClO+1 have different electronic arrangement (geometry) at central atom S3 : SF2Cl2 , IOCl4– and F2ClO+ have equal number of lone pairs of electrons at the central atom. S4 : All bond angle in each of species , XeOF4 , IOCl4– , SF2Cl2 and F2ClO+ are identical The correct order for the above statements is : (A) F T T F (B) F F F F (C) T T F F (D) T F T F 95. S1 : In CrO5 , the oxidation number of Cr is +6. S2 : Out of CH3Cl and CHCl3, CH3Cl has higher dipole moment S3 : Hybridisation of sulphur in SO3 and in its trimer is the same, sp2 . (A) T F T 96. (B) T T F (C) T F F Given the species N2, CO, CN– and NO+ . Which of the following statement is incorrect . (A) All the species are diamagnetic (B) All the species are isoelectronic (C) All the species have dipole moment (D) All the species are linear (D) T T T 97. Which of the following are incorrect for dipole moment ? (A) Lone pair of elements present on central atom can give rise to dipole moment (B) Dipole moment is vector quantity (C) PF5 (g) molecule has non zero dipole moment (D) Difference in electronegativities of combining atom can lead to dipole moment 98. Which of the following orders are correct regarding mentioned properties (A) SO3 < CCl4 < XeF2 (Bond angle). (B) SOF2 > SOCl2 > SOBr2 (Bond angle) (C) CH3COO– > CO32– > CH3COCH3 (C — O bond length) (D) CH3Cl > CH3F < CD3F (dipole moment). 99. CH3Cl has more dipole moment than CH3F because : (A) electron affinity of chlorine is greater than that of fluorine. (B) the charge separation is larger in CH3Cl compared to CH3F. (C) the repulsion between the bond pairs and non-bonded pairs of electrons is greater in CH3Cl than CH3F. (D) chlorine has higher electronegativity than fluorine. 100. S1 : In ozone molecule, O – O bond lengths are equal, this can be explained on the basis of resonance. S2 : Ion-dipole attraction is responsible for hydration of ions. S3 : Intermolecular H-bonding decreases the boiling point. S4 : A symmetrical molecule with identical bonds have non zero dipole moment. (A) T F T F (B) T T F T (C) T T F F (D) T T T F 101. H - bonding is maximum in (A) C 6 H 5 OH (B) C 6 H 5COOH (C) CH 3 CH 2 OH (D) CH 3 COCH 3 102. Give the correct order of initials T or F for following statements. Use T if statement is true and F if it is false. S1 : HF boils at a higher temperature than HCl S2 : HBr boils at lower temperature than HI S3 : Bond length of N2 is less than N2+ S4 : F2 has higher boiling point than Cl2 (A) T F T T (B) T T F F (C) T T T F (D) T T T T 103. The increasing order of the strength of hydrogen bond in the following mentioned linkages is : (i) O—H---S (ii) S—H---O (iii) F—H---F (iv) F—H---O (A) (i) < (ii) < (iv) < (iii) 104. 105. (B) (ii) < (i) < (iv) < (iii) (C) (i) < (ii) < (iii) < (iv) Which one of the following does not have intermolecular H-bonding ? (A) H2O (B) o-nitro phenol (C) HF (D) (ii) < (i) < (iii) < (iv) (D) CH3COOH Which of the following compounds would have significant intermolecular hydrogen bonding ? HF, CH 3 OH, N 2 O 4 , CH 4 , NH 3  l  (A) HF, N2O4 , NH3  l  106. (B) HF, CH 4 , CH 3OH (C) HF, CH3OH, NH3  l  (D) CH3OH, CH 4 , NH3  l  Select the correct statement. (A) The order of Xe–F bond length in various fluorides of Xenon is XeF2 < XeF4 < XeF6 (B) PH5 can undergo sp3d hybridisation to have octahedral geometry. (C) Dipole moment of CH3F is greater than that of CH3Cl (D) Increasing strength of hydrogen bonding is Cl–H----Cl < N–H----N < O–H----O < F–H----F CHEMICAL BONDING 107. Consider the following statements. S1 : The percentage of s-character in the orbital forming S – S bonds and P – P bonds in S8 and P4 molecules respectively are same. S2 : In SF4 the bond angles, instead of being 90º and 180º are 89º and 177º respectively due to the repulsions between lone pair and bond pairs of electrons. S3 : Aqueous H3PO4 is syrupy (i.e more viscous than water) S4 : SiO2 crystal may be considered as giant molecule in which eight-membered rings are formed with alternate silicon and oxygen atoms. Of these : (A) S1 & S4 are correct only. (B) S2, S3 & S4 are correct only. (C) S1, S2, S3 & S4 are correct. (D) S1,S2 & S3 are correct only. 108. Select the correct statement for the sulphuric acid. (I) It has high boiling point and viscosity. (II) There are two types of bond lengths in its bivalent anion. (III) p-d bonding between sulphur and oxygen is observed. (IV) Sulphur has the same hybridisation that is of boron in diborane. 109. 110. (A) II and III only (B) II, III and IV only (C) I, III and IV only (D) III and IV only Intermolecular hydrogen bonding increases the enthalpy of vaporization 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. S1 : The polarising power of a cation and polarisability of an anion, both are directly proportional to their sizes. S2 : H2+ and He2+ have same bond order but H2+ is more stable than He2+ . S3 : The strength of hydrogen bond does not depend at all on the availability of the lone pair of electrons on the atom forming H-bond. S4 : OF2 and Cl2O both are sp3 hybridised and bond angle in Cl2O is greater than 109º28’. (A) T F F T (B) F F F T (B) F T F T (D) T T T T 111. 112. 113. Which of the following has minimum melting point (A) CsF (B) HCl (C) HF Which of the following statemets is true? (A) The dipole moment of NF3 is zero (B) The dipole moment of NF3 is less than NH3 (C) The dipole moment of NF3 is more than NH3 (D) The dipole moment of NH3 is zero Among the following compounds, the correct order of the polarity of the bonds is : (A) SbH3 < AsH3 < PH3 < NH3 (C) PH3 < AsH3 < SbH3 < NH3 114. (D) LiF SbH3 , AsH3 , PH3 , NH3 . (B) AsH3 < SbH3 = PH3 < NH3 (D) AsH3 < PH3 < SbH3 < NH3 Among the following, van der Waals forces are maximum in : (A) HBr (B) LiBr (C) LiCl (D) AgBr 115. Intermolecular hydrogen bond is present in which of the following pair of molecules ? (A) SiH4 and SiF4 O || (B) CH3  C  CH3 and CHCl3 O O || || (C) H  C  OH and CH3  C  OH (D) CH3OCH3 and H2O2 116. Among the following compounds the one that is polar and has central atom with sp3 hybridisation is : (A) H2CO3 (B) SiF4 (C) BF3 (D) HClO2 117. Which of the following are polar (A) XeF4 (B) SO3 (C) XeOF4 (D) ICl4– Which of the following exhibits H-bonding ? (A) CH4 (B) H2Se (C) N2H4 (D) H2S 118. 119. Bicarbonate (HCO3–) exists in KHCO3 and NaHCO3 respectively as : (A) Dimeric and polymeric chain like structure. (B) Polymeric chain and dimeric structure. (C) Dimeric and trimeric structure. (D) Trimeric and dimeric structure. 120. Covalent compounds have low melting point because (A) Covalent bond is less exothermic (B) Covalent molecules have definite shape (C) Covalent bond is weaker than ionic bond 121. 122. (D) Covalent molecules are held by weak Vander Waal's force of attraction The bond that determines the secondary structure of a protein is (A) Coordinate bond (B) Covalent bond (C) Hydrogen bond (D) Ionic bond Pure phosphoric acid is very viscous, because : (A) It is a strong acid (B) It is tribasic acid (C) It is hygroscopic (D) It has PO43- groups which are bonded by many hydrogen bonds 123. Which of the following is least volatile ? (A) HF 124. (B) HCl (C) HBr (D) HI Which of the following is false ? (A) Van der Waals forces are responsible for the formation of molecular crystals. (B) Branching lowers the boiling points of isomeric organic compounds due to reduction in the van der Waals force of attraction. (C) In graphite, van der Waals forces act between the carbon layers. (D) Boiling point of NH3 is greater than SbH3. CHEMICAL BONDING 125. SnCl2.2H2O readily loses one molecule of water at 800 C because : (A) One water molecule is coordinated to lone pair of electrons on SnCl 2 and the other is hydrogen bonded to coordinated water molecule. (B) One water molecule is bonded to SnCl2 by coordinate covalent bond and the other is held by iondipole attractive forces to central metal ion. (C) Both the water molecules are coordinated to lone pairs of electrons on pyramidal SnCl2 . (D) Both the water molecules are bonded to pyramidal SnCl2 by hydrogen bonds. 126. The pairs of bases in DNA are held together by (A) Hydrogen bonds (C) Phosphate groups (B) Ionic bonds (D) Deoxyribose groups [Assertion & Reason Type Questions] Part # II Each question has 5 choices (A), (B), (C), (D) and (E) out of which only one is correct. (A) Statement-1 is true, Statement-2 is true and Statement-2 is correct explanation for Statement-1 (B) Statement-1 is true, Statement-2 is true and Statement-2 is not correct explanation for Statement-1 (C) Statement-1 is true, Statement-2 is false (D) Statement-1 is false, Statement-2 is true (E) Both Statements are false 1. Statement-1 : The bond angles of BrNO , CINO and FNO are approximately 114.50 , 113.30 and 110.10 respectively. Statement-2 : The hybridisation of central N atom in all three compounds is sp2. 2. Statement-1 : All F-S-F angles in SF4 are greater than 90º but less than 180º. Statement-2 : The bond pair-bond pair repulsion is weaker than lone pair-bond pair repulsion. 3. Statement-1 : In tetrahedral hybridisation i.e., in sp3 hybridisation all p–orbitals of valence shell are involved and no p–orbital is left for forming –bonds. Statement-2 : Central atom can not form double bonds in the molecules or species having sp3 hybridisation. 4. Statement-1 : Molecular species like SF6, PF5 , I3– and XeF2 violate the octet rule. Statement-2 : Compounds with an expanded octet are called hypervalent compounds. 5. Statement-1 : [SiCl6]2 – does not exist. Statement-2 : Interaction between lone pairs of chloride ions and Si4+ is not very strong and six large chloride ions can not be accommodated around Si4+ due to limitation of its size. 6. Statement-1 : In CH3NCO , the bond angles C – N – C and N – C – O are not identical. Statement-2 : N–atom has a lone pair of electrons which is involved in p-d delocalisation where as C–atom does not have lone pair of electrons. F Q 7. Statement-1 : F Bond angle R is a normal triangular angle 1200. R P F F Statement-2 : P  1800 ; Q  900 and thus R  1200 but less then 1200 due to the presence of a lone pair.. 8. Statement-1 : In IOF4 – a single lone pair is present on iodine atom trans to oxygen atom to have minimum repulsion between the I = O and the lone pair of electrons. Statement-2 : The VSEPR model considers double and triple bonds to have slightly greater repulsive effect than single bonds because of the repulsive effect of  electrons. 9. Statement-1 : Molecules having different hybridisation can have same shape. Statement-2 : The shape of a molecule does not depend on the hybridisation but it depends on the energy factor. 10. Statement-1 : SO2 , NO3– and CO32– are isoelectronic as well as isostructural species. Statement-2 : The d and f–orbitals do not shield the nuclear charge very effectively. Therefore , there is significant reduction in the size of the ions , just after d or f orbitals have been completely filled. CHEMICAL BONDING 11. Statement-1 : NO3– and PO3– have similar formula type but differ structurally i.e. they have different type of hybridisation. Statement-2 : NO3– ion exists as free ion. On the other hand PO3– exists as cyclic or linear polymeric structure. 12. Statement-1 : Carbon has unique ability to form p–p multiple bonds with itself and with other atoms of small size and high electronegativity. Statement-2 : Heavier elements of group 14th do not form p–p bonds because their atomic orbitals are too large and diffuse to have effective side ways overlapping. 13. Statement-1 : Elemental nitrogen exists as a diatomic molecule and phosphorous as tetratomic molecule. Statement-2 : Nitrogen does not have vacant d–orbital whereas phosphorus have vacant d–orbital. 14. Statement-1 : Single N–N bond is weaker than the single P–P bond. Statement-2 : In N–N bond there is high interelectronic repulsion of the non–bonding electrons, owing to the weaker bond. 15. Statement-1 : The hybridisation of N atom in acetamide is sp3. Statement-2 : There occurs delocalisation of lone pair of electrons present on N atom. F P 16. Statement-1 : F , bond angle P is equal to the bond angle Q but not precisely equal to 900. Q F Statement-2 : The molecule is T -Shaped and there is repulsion between lone pairs of electrons 17. Statement-1 : The electronic structure of azide ion (N3–) is Statement-2 : . is not a resonating structure of azide ion, because the position of atoms cannot be changed. 18. Statement-1 : Si – F , Si – Cl and Si – O bonds are stronger than the corresponding bonds with C. Statement-2 : ++ - - - + F p – d overlapping Si 19. Statement-1 : Aluminium chloride in acidified aqueous solution forms octahedral [Al(H2O)6]3+ ion. Statement-2 : In [Al(H2O)6]3+ complex ion, the 3d orbitals of Al are involved and the hybridisation state of Al is sp3d2. 20. Statement-1 : In graphite, on increasing the temperature the conductivity decreases along the layers of carbon atoms. Statement-2 : Graphite cleaves easily, because the force of attraction between the layers is weak van der Waal’s force. 21. Statement-1 : A molecule of buckminister fullerene exhibits aromatic character. Statement-2 : All the carbon atoms undergo sp2 hybridisation. Each carbon atom forms three sigma bonds with other three carbon atoms. The remaining electron at each carbon is delocalised in molecular orbitals. 22. Statement-1 : Amongst the oxo acids of halogens, HOCl , HOBr and HOI, the HOI is the most acidic acid. Statement-2 : The conjugate base stability is CIO – > BrO – > IO – 23. Statement-1 : PF5 keeps trigonal bipyramidal structure in gas as well as in solid state. Statement-2 : PCl5 in gas and liquid state is covalent but in solid state it is ionic and exist as [PCl4]+ and [PCl6]– 24. Statement-1 : The double bond in C2 molecule consists of both -bonds. Statement-2 : Four electrons are present in two –bonding molecular orbitals in C2. 25. Statement-1 : Anhydrous AlCl3 is more soluble in diethyl ether than hydrous AlCl3. Statement-2 : Anhydrous AlCl3 is electron deficient. The oxygen atom of ether donates a pair of electrons to vacant p–orbital on the Al atom forming a co-ordinate bond. 26. Statement-1 : Atomic orbitals are monocentric while molecular orbitals are polycentric. Statement-2 : In an atomic orbital the movement of an electron is influenced by only one positive nucleus, while that of an electron in a molecular orbital is influenced by two or more nuclei depending on the number of atoms contained in the molecule. 27. Statement-1 : To obtain effective p–d overlap , the size of the d–orbital must be similar to the size of the p–orbital. So for chlorine p–d bonding is strongest in their oxoanions. Statement-2 : On moving a period from left to right in the periodic table , the nuclear charge is increased and more s and p-electrons are added. Since these s– and p–electrons shield the nuclear charge incompletely, the size of the atom and that of the d–orbitals decreases. This leads to progressively stronger p–d bonding. 28. Statement-1 : Dimethyl ether and disilyl ether both readily form complexes with trimethyl borane Statement-2 : 29. Statement-1 : Solubility of LiI is more than that of LiBr. Statement-1 : LiI has more lattice energy and more hydration energy in comparison to LiBr. 30. Statement-1 : Al3+ form more ionic compound in comparison to Ga3+, with identical anion. Statement-2 : rAl3+  rGa3+ and Zeff of Ga3+ is more than that of Al3+. 31. Statement-1 : Ortho boric acid crystal are hard and cannot be broken easily into the powder form. Statement-2 : In the solid state B(OH)3 units are hydrogen bonded together into two dimensional sheets. 32. Statement-1 : The crystal structures of NaHCO3 and KHCO3 , both show intermolecular hydrogen bonding but are different. Statement-2 : In NaHCO3 the HCO3– ions are linked together through intermolecular hydrogen bonds into an infinite chain , while in KHCO3 , HCO3– ions form dimeric anions through intermolecular hydrogen bonds. CHEMICAL BONDING 33. Statement-1 : Fluorine (F2) is gas while iodine (I2) is solid at room temperature. Statement-2 : A larger molecule or heavy atom is more polarizable and has larger dispersion forces because it has many electrons some of which are less tightly held and are farther from the nucleus. 34. Statement-1 : Noble gases are liquefied at very low temperature. Hence they have low boiling points. Statement-2 : Noble gases being monoatomic have no other interatomic forces except weak dispersion forces. 35. Statement-1 : NF3 has little tendency to act as a donor molecule. Statement-2 : The highly electronegative F atoms attract electrons and these moments partly cancel the moment from the lone pair. 36. Statement-1 : Fluoromethane (CH3 F ;  = 1.85 D) has a smaller dipole moment than chloromethane (CH3Cl ;  = 1.87 D) Statement-2 : Fluorine has less electron affinity than that of chlorine. 37. Statement-1 : Acetylene is not soluble in H2O but is highly soluble in acetone. Statement-2 : Acetylene forms inter molecular H–bond with acetone easily but not with H2O as water molecular themselves are highly associated through inter molecular H–bonds. 38. Statement-1 : Crystals of hydrated calcium sulphate (gypsum : (CaSO4 . 2 H2O)) are soft and easily cleaved. Statement-2 : Crystals of anhydrous calcium sulphate (anhydride : CaSO4) are very hard and very difficult to cleave. 39. Statement-1 : In case of persulphuric acid, the K1 >> K2 . Statement-2 : The anion of persulphuric acid is intermolecular hydrogen bonded. EXERCISE - 2 : PART # I 1. 5. 9. 13. 17. 21. B, C, D B, C A, C A, B, C, D A, C A, B, C 2. 6. 10. 14. 18. 22. B,C B, D A, B B, C C, D B, C 3. 7. 11. 15. 19. 23. A, B, C, D A, B B, C, D B, D B, C A, B, C 4. 8. 12. 16. 20. 24. B, C A, B, C A, C A, B, C A, C, D B, D 25. D 26. A,B,C 27. A, B, C, D 28. A, B, D 29. 33. 37. B, C, D A, B, C A, B,D 30. 34. 38. A, B, C B, D B, C, D 31. 35. 39. B, C, D A, B, C, D A, B, C, D 32. 36. 40. B, C, D A, B, C A, B, D 41. A, B, C, D 42. A, B, C, D 43. B, C, D 44. B, C, D 45. 49. 61. A 74. A 87. D 100. C 113. C 126. A B, D A, C 62. A 75. D 88. B 101. B 114. D 46. 50. A 51. A 63. B 64. A 76. B 77. A 89. B 90. D 102. B 103. A 115. C 116. D A, B, D 52. C 65. A 78. B 91. C 104. B 117. C 47. 53. C 54. B 66. D 67. D 79. C 80. D 92. C 93. C 105. C 106. D 118. C 119. A D 55. B 68. A 81. C 94. A 107. C 120. D 48. 56. A 57. D 69. D 70. A 82. D 83. D 95. B 96. D 108. C 109. B 121. C 122. D B, C 58. D 71. D 84. D 97. C 110. B 123. A 59. D 72. C 85. D 98. D 111. B 124. D 60. C 73. B 86. D 99. B 112. B 125. A 11. A 24. A 37. A 12. B 25. A 38. B 13. B 26. A 39. C PART # II 1. B 14. A 27. A 2. D 15. D 28. D 3. C 16. A 29. C 4. B 17. B 30. A 5. A 18. A 31. D 6. C 19. A 32. A 7. D 20. B 33. A 8. A 9. A 21. As 22. D 34. A 35. A 10. D 23. B 36. B