Chemical Bonding Exercise # 5

CHEMICAL BONDING Exercise # 5 1. 2. Part # I [Previous Year Questions] The correct order of bond angles (smallest first) in H2S, NH3, BF3 and SiH4 is :– (1) H2S < NH3 < SiH4 < BF3 (2) NH3 < H2S < SiH4 < BF3 (3) H2S < SiH4 < NH3 < BF3 (4) H2S < NH3 < BF3 < SiH4 The bond order in NO is 2.5 while that in NO+ is 3. Which of the following statements is true for these two species ? (1) Bond length in NO+ is equal to that in NO (2) Bond length in NO is greater than in NO+ (3) Bond length in NO+ is greater than in NO (4) Bond length is unpredictable 3. The states of hybridization of boron and oxygen atoms in boric acid (H3BO3) are respectively (1) sp3 and sp2 (2) sp2 and sp3 (3) sp2 and sp2 (4) sp3 and sp3 4. Which one of the following has the regular tetrahedral structure ? (1) BF4– (2) SF4 (3) XeF4 (4) [Ni(CN)4]2– (Atomic nos.: B = 5, S = 16, Ni = 28, Xe = 54) 5. 6. 7. The maximum number of 90° angles between bond pair-bond pair of electrons is observed in :(1) dsp2 hybridization (2) sp3d hybridization (3) dsp3 hybridization (4) sp3d2 hybridization Beryllium and aluminium exhibit many properties which are similar. But, the two elements differ in (1) Forming covalent halides (2) Forming polymeric hydrides (3) Exhibiting maximum covalency in compounds (4) Exhibiting amphoteric nature in their oxides Which one of the following species is diamagnetic in nature ? (1) He2+ 8. 9. (2) H2 (3) H2+ lattice energy of an ionic compound depends upon (1) charge on the ion only (2) size of the ion only (3) packing of the ion only (4) charge and size of the ion The molecular shapes of SF4, CF4 and XeF4 are (1) the same with 2, 0 and 1 lone pair of electrons on the central atom, respecitvely (2) the same with 1, 1 and 1 lone pair of electrons on the central atoms, respectively (3) different with 0, 1 and 2 lone pair of electrons on the central atoms, respectively (4) different with 1, 0 and 2 lone pair of electrons on the central atoms, respectively (4) H2– 10. Of the following sets which one does not contain isoelectronic species ? 3– 2– 2– 2– – – (1) PO4 , SO4 , ClO4 – 3– (3) SO3 , CO3 , NO3 11. 13. 14. 16. (3) O 22  (4) B2 (2) benzene and carbon tetrachloride (3) benzene and ethanol (4) acetonitrile and acetone A metal, M forms chlorides in its +2 and +4 oxidation states. Which of the following statements about these chlorides is correct? (1) MCl2 is more ionic than MCl4 (2) MCl2 is more easily hydrolysed than MCl4 (3) MCl2 is more volatile than MCl4 (4) MCl2 is more soluble in anhydrous ethanol than MCl4 In which of the following molecules/ions are all the bonds not equal? (2) BF4– (3) SF4 (4) SiF4 The decreasing values of bond angles from NH3 (106°) to SbH3 (91°) down group-15 of the periodic table is due to (1) decreasing lp – bp repulsion (2) increasing electronegativity (3) increasing bp – bp repulsion (4) increasing p-orbital character in sp3 In which of the following ionizion processes, the bond order has increased and the magnetic behaviour has changed (2) O2  O 2 (3) N2 N 2 (4) C2  C 2 (3) O–H.....F (4) O–H.....N Which of the following hydrogen bonds is the strongest (1) F–H.....F 18. (2) O2 (1) KCl and water (1) NO NO+ 17. – Among the following mixtures, dipole-dipole as the major interaction, is present in (1) XeF4 15. 2– (4) BO3 , CO3 , NO3 Which of the following molecules\ions does not contain unpaired electrons? (1) N 2 12. 2– (2) CN , N2, C2 (2) O–H.....O Which of the following species exhibits the diamagnetic behaviour (1) O 2 (2) O2 (3) NO (4) O 22  CHEMICAL BONDING 19. 20. The charge/size ratio of a cation determines its polarizing power. Which one of the following sequences represents the increasing order of the polarizing power of the cationic species, K+, Ca+2, Mg+2, Be+2 (1) Be+2 < K+ < Ca+2 < Mg+2 (2) K+ HClO3 > HClO2 > HOCl (2) HClO2 > HClO4 > HClO3 > HOCl (3) HOCl > HClO2 > HClO3 > HClO4 (4) HClO4 > HOCl > HClO2 > HClO3 Which among the following is the most reactive ? (1) I2 33. (4) Br2 (2) Xe (3) He (4) Ne The species in which the N atom is in a state of sp hybridization is: (1) NO–2 35. (3) Cl2 Which one has the highest boiling point? (1) Kr 34. (2) ICl (2) NO–3 (3) NO2 (4) NO2 The pair in which phosphorous atoms have a formal oxidation state of +3 is : (1) Pyrophosphorous and hypophosphoric acids (2) Orthophosphorous and hypophosphoric acids (3) Pyrophosphorous and pyrophosphoric acids (4) Orthophosphorous and pyrophosphorous acids 36. The reaction of zinc with dilute and concentrated nitric acid, respectively, produces: (1) NO2 and NO 37. (2) NO and N2O (3) NO2 and N2O (4) N2O and NO2 Which of the following compounds is metallic and ferromagnetic ? (1) CrO2 (2) VO2 (3) MnO2 (4) TiO2 CHEMICAL BONDING 38. The species in which the N atom is in a state of sp hybridization is: (1) NO 2– 39. 40. 41. (3) O2– , F– , Na, Mg2+ (4) O– , F– , Na+ , Mg2+ (3) 12 (4) 3 Total number of lone pair of electrons in I 3 ion is : (4) He 22  [Previous Year Questions] (B) Paramagnetic and Bond order > O2 (C) Diamagnetic and Bond order < O2 (D) Diamagnetic and Bond order > O2 Which species has the maximum number of lone pair of electrons on the central atom? (B) XeF4 (C) SF4 (D) I3– The percentage of p-character in the orbitals forming P–P bonds in P4 is (B) 33 (C) 50 (D) 75 (C) N2O (D) KO2 Among the following, the paramagnetic compound is (B) O3 The species having bond order different from that in CO is (A) NO– 6. (3) H 22  (A) Paramagnetic and Bond order < O2 (A) Na2O2 5. (2) H 2 According to molecular orbital theory which of the following statement about the magnetic character and bond order is correct regarding O2+ (A) 25 4. (2) 9 According to molecular orbital theory, which of the following will not be a viable molecule ? (A) ClO3– 3. (4) NO +2 The group having isoelectronic species is : (1) O2– , F– , Na+ , Mg2+ (2) O– , F– , Na, Mg+ Part # II 2. NO 2 (4) B2 (1) He2 1. (3) Which of the following species in not paramagnetic ? (1) NO (2) CO (3) O2 (1) 6 42. (2) NO 3– (B) NO+ (C) CN– (D) N2 (B) planar (C) pyramidal (D) T-shaped The structure of XeO3 is (A) linear 7. Statement-1 : p-Hydroxybenzoic acid has a lower boiling point than o-hydroxybenzoic acid. Statement-2 : o-Hydroxybenzoic acid has intramolecular hydrogen bonding. (A) Statement-1 is True, Statement-2 is True; Statement-2 is a correct explanation for Statement-1. (B) Statement-1 is True, Statement-2 is True; Statement-2 is NOT a correct explanation for Statement-1. (C) Statement-1 is True, Statement-2 is False. (D) Statement-1 is False, Statement-2 is True. 8. Statement-1 : In water, orthoboric acid behaves as a weak monobasic acid. Statement-2 : In water, orthoboric, acid acts as a proton donor. (A) Statement-1 is True, Statement-2 is True; Statement-2 is a correct explanation for Statement-1. (B) Statement-1 is True, Statement-2 is True; Statement-2 is NOT a correct explanation for Statement-1. (C) Statement-1 is True, Statement-2 is False. (D) Statement-1 is False, Statement-2 is True. 9. Statement-1 : Pb+4 compounds are stronger oxidizing agents than Sn4+ compounds Statement-2 : The higher oxidation states for the group 14 elements are more stable for the heavier members of the group due to 'inert pair effect' . (A) Statement-1 is True, Statement-2 is True; Statement-2 is a correct explanation for Statement-1. (B) Statement-1 is True, Statement-2 is True; Statement-2 is NOT a correct explanation for Statement-1. (C) Statement-1 is True, Statement-2 is False. (D) Statement-1 is False, Statement-2 is True. 10. Match each of the diatomic molecules in Column I with its property / properties in Column II. Column I 11. (A) B2 (P) Paramagnetic (B) N2 (Q) undergoes oxidation (C) O2– (R) Undergoes reduction (D) O2 (S) Bond order  2 (T) Mixing of 's' and `p' orbitals The nitrogen oxide(s) that contain(s) N–N bond(s) is (are) (A) N2O 12. Column II (B) N2O3 (C) N2O4 (D) N2O5 (C) (CH3)2NH (D) (CH3)3N In the reaction 2X + B2H6  [BH2(X)2]+ [BH4]– the amine(s) X is (are) (A) NH3 (B) CH3NH2 CHEMICAL BONDING 13. The species having pyramidal shape is (A) SO3 14. (B) 0 and diamagnetic 17. 19. (C) 1 and paramagnetic (D) 0 and paramagnetic (B) sp and sp2 (D) sp2 and sp3 Which ordering of compounds is according to the decreasing order of the oxidation state of nitrogen(A) HNO3, NO, NH4Cl, N2 (B) HNO3, NO, N2, NH4Cl (C) HNO3, NH4Cl, NO, N2 (D) NO, HNO3, NH4Cl, N2 The shape of XeO2F2 molecule is : (A) Trigonal bipyramidal 18. (D) OSF2 In allene (C3H4), the type(s) of hybridisation of the carbon atoms is (are) (A) sp and sp3 (C) only sp2 16. (C) SiO2– 3 Assuming that Hund's rule is violated, the bond order and magnetic nature of the diatomic molecule B 2 is (A) 1 and diamagnetic 15. (B) BrF3 (B) Square planar (C) tetrahedral (D) see-saw The pair(s) of reagents that yield paramagnetic species is/are (A) Na and excess of of NH3 (B) K and excess of O2 (C) Cu and dilute HNO3 (D) O2 and 2-ethylanthraquinol The correct statement(s) for orthoboric acid is/are (A) It behaves as a weak acid in water due to self ionization. (B) Acidity of its aqueous solutoin increases upon addition of ethylene glycol. (C) It has a three dimensional structure due to hydrogen bonding. (D) It is weak electrolyte in water 20. Assuming 2s-2p mixing is NOT operative, the paramagnetic species among the following is : (A) Be2 (B) B2 (C) C2 (D) N2 21. The total number of lone pairs of electrons in N2O3 is. 22. Among the triatomic molecules/ions, BeCl2 , N–3 , N2O, NO2 , O3, SCl3, ICl–2 , I–3 , and XeF2, the total number of linear molecule(s)/ion(s) where the hybridization of the central atom does not have contribution from the d-orbital(s) is [Atomic number: S = 16, Cl = 17, I = 53 and Xe = 54] 23. The correct statement(s) regarding, (i) HClO, (ii) HClO2, (iii) HClO3 and (iv) HClO4 is (are) (A) The number of Cl = O bonds in (ii) and (iii) together is two (B) The number of lone pairs of electrons on Cl in (ii) and (iii) together is three (C) The hybridixation of Cl in (iv) is sp3 (D) Amongst (i) to (iv), the strongest scid is (i) 24. 25. Under hydrolytic conditions, the compounds used for preparation of linear polymer and for chain termination, respectively, are (A) CH3SiCl3 and Si(CH3)4 (B) (CH3)2SiCl2 and (CH3)3SiCl (C) (CH3)2SiCl2 and CH3SiCl3 (D) SiCl4 and (CH3)3SiCl The compound(s) with TWO lone pairs of electrons on the central atom is(are) (A) BrF5 26. (B) ClF3 (C) XeF4 (D) SF4 According to Molecular Orbital Theory, (A) C22  is expected to be diamagnetic (B) O22  is expected to have a longer bond length than O2 (C) N 2 and N 2 have the same bond order (D) He 2 has the same energy as two isolated He atoms Subjective 27. Decreasing order of the O-O bond length present in them O2, KO2 and O2 [AsF4] 28. The number of water molecule(s) directly bonded to the metal centre in CuSO4.5H2O is 29. Based on VSEPR theory, the number of 90 degree F–Br–F angles in BrF5 is 30. The value of n in the molecular formula BenAl2Si6O18 is 31. The total number of diprotic acids among the following is 32. H3PO4 H2SO4 H3BO3 H3PO2 H2CO3 CrO4 H2SO3 2 H2S2O7 Among the following, the number of elements showing only one non-zero oxidation state is O, 33. H H3PO3 Cl, F, N, P, Sn, Tl, Na, Ti The difference in the oxidation numbers of the two types of sulphur atoms in Na2S4O6 is. CHEMICAL BONDING 34. The sum of the number of lone pairs of electrons on each central atom in the following species is – [TeBr6]2–, [BrF2]+, SNF3, and [XeF3]– (Atomic numbers : N = 7, F = 9, S = 16, Br = 35, Te = 52, Xe = 54) 35. Among H2, He2+, Li2, Be2, B2, C2, N2, O2– and F2, the number of diamagnetic species is (Atomic numbers : H = 1, He = 2, Li = 3, Be = 4, B = 5, C = 6, N = 7, O = 8, F = 9) EXERCISE - 5 : PART # I 1. 1 2. 2 3. 3 4. 1 5. 4 6. 3 7. 2 8. 4 9. 4 10. 3 11. 3 12. 4 13. 1 14. 3 15. 4 16. 1 17. 1 18. 4 19. 2 20. 3 21. 4 22. 2 23. 1 24. 4 25. 1 26. 3 27. 1 28. 4 29. 4 30. 3 31. 1 32. 2 33. 2 34. 4 35. 4 36. 4 37. 1 38. 4 39. 2 40. 1 41. 2 42. 3 12. B,C 13. D 14. A 15. B PART # II 1. B 2. D 3. D 4. D 5. A 6. C 7. D 8. C 9. C 10. A  (P,Q,R,T) ; B  Q,R,S,T ; C  (P,Q,R) ; D  (P,Q,R,S) 11. A,B,C 16. B 17. D 18. A,B,C 19. B,D 20. C 21. 8 22. 4 23. B,C 30. 3 31. 6 32. 2 33. 5 24. B 25. B, C Subjective Questions 27. KO2 > O2 > O2 [AsF4] 28. 4 29. 0 34. 6 35. 5 or 6 26. A, C