Q. 01 Encircle The best Option.

1. Bond angle of 109°.5’ is found in:

(a) NH3                                                 (b) H2O                                                                 (c) CH3+                                 (d) +NH4

2. Hybridization of the underlined atom changes in which of the following transitions?

(a) AIH3 changes to AlH4                                                                              (b) H2O changes to H3O+             

(c) NH3 changes to +NH4                                                                                            (d) in all cases

3. The number of lone pairs on Xe in XeF2, XeF4 and XeF6 respectively are:

(a) 3, 2, 1                                              (b) 2, 4, 6                                             (c) 1, 2, 3                              (d) 6, 4, 2

4.Which of the following is a linear molecule?

 (a) SO2                                                (b) CH4                                                                 (c) H2O                                 (d) BeCl2

5. Which of the following hydrogen bonds is the strongest?

(a) F–H….F                                          (b) O–H….O                                        (c) O–H….F                          (d) O–H….N

6. Which one of the following pairs of species have the same bond order?

(a) CN– and NO+                                                                                              (b) CN– and CN+                             

(c) O2– and CN–                                                                                               (d) NO+ and CN+

7. Which of the following species exhibits the diamagnetic behaviour?

(a) O2+                                                   (b) O2                                                    (c) NO                                   (d) O2-2

8. In which of the following compounds will the bond angle be maximum?

(a) NH3                                                 (b) NH4+                                               (c) PCl3                                  (d) SCl2

9. 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+, Ca2+, Mg2+, Be2+?

(a) Be2+ < K+ < Ca2+ < Mg2+                                                                      (b) K+ < Ca2+ < Mg2+ < Be2+

(c) Ca2+ < Mg2+ < Be2+ < K+                                                                      (d) Mg2+ < Be2+ < K+ < Ca2+

10. Which of the following is an electron deficient molecule?

(a) C2H6                               (b) PH3                                                 (c) B2H6                               (d) SiH4

11. In which of the following molecules/ions all the bonds are unequal?

(a) SF4                                 (b) SiF4                                                 (c) XeF4                                (d) BF4 –

12. Among the following pairs, the one in which the two species are not isostructural is:

(a) SiF4 and SF4                (b) IO3 – and XeO3          (c) BH4 – and NH4 +        (d) PF6 – and SF6

13. In which of the following ionization processes, the bond order has increased and the magnetic behaviour has changed?

(a) NO → NO+                   (b) O2 → O2+                    (c) N2 → N2+                     (d) C2 → C2+

14. Number of P-O bonds in P4O10 is:

(a) 17                                     (b) 16                                    (c) 15                                     (d) 6

15. Of the following sets which does not contain isoelectronic species?

(a) SO3 2–, CO3 2–, NO3 –                                            (b) CN–, N2, C2 2–

(c) BO3 3–, CO3 2–, NO3 –                                            (d) PO4 3–, SO4 2–, ClO4 –

16. The pair of species having identical shapes for molecules of both species is:

(a) CF4, SF4                         (b) XeF2, CO2                    (c) BF3, PCl3                       (d) PF5, IF5

17. In which of the following molecules all the bonds are not equal?

(a) AlF3                                 (b) NF3                                  (c) ClF3                                  (d) BF3

18. Which of the following molecules/ions does not contain unpaired electrons?

(a) O2                                   (b) B2                                     (c) N2+                                   (d) O2

19. Which of the following is an electron deficient molecule?

(a) C2H6                               (b) NH3                                (c) BeCl2                              (d) SiCl4

20. The number and type of bonds between two carbon atoms in calcium carbide are:

(a) One sigma, two pi     (b) Two sigma, two pi     (c) One sigma, one pi     (d) Two sigma, one pi

21. The ratio of π and α bonds in benzene is:

(a) 1 : 2                                 (b) 1 : 4                                (c) 1 : 6                                  (d) 1 : 6

22. The bond length between C-C bond in sp3 hybridized molecule is:

(a) 1.2 Å                               (b) 1.39 Å                             (c) 1.33 Å                             (d) 1.54 Å

23. The planar structure of BF3 can be explain by the fact that BF3 is:

(a) sp hybridized              (b) sp2 hybridized           (c) sp3 hybridized            (d) sp3 hybridized

24. Dipole moment is shown by:

(a) 2-methyl propane     (b) Trans-2-butene         (c) Cis-2-butene               (d) Carbon tetrachloride

25. O2has a bond order of:

(a) 1                                       (b) 2                                       (c) 3                                       (d) 4

26. In 1, 3-butadiene, the carbon is hybridized as:

(a) sp                                     (b) sp2                                  (c) sp3                                   (d) sp2 and sp3

27. The most polar covalent species among the ones listed is:

(a) C–S                                  (b) C–O                                (c) C–F                                  (d) C–Br

28. Correct order of polarizing power is:

(a) Cs+ < K+ < Mg2+ < Al3+                                          (b) K+ < Cs+ < Mg2+ < Al3+

(c) Cs+ < K+ < Al3+ < Mg2+                                          (d) K+ < Cs+ < Al3+ < Mg2+

29. H-bond is strongest in:

(a) C2H5OH                         (b) H–F                                                 (c) H2O                                 (d) CH3COCH3

30. Hybridization of 1 and 2 carbon atom in 1CH2= 2C=CH2 are:

(a) sp, sp                              (b) sp2, sp2                         (c) sp2, sp                            (d) sp3, sp2

31. Which of the following molecules contains one lone pair of electrons on the central atom?

(a) NH3                                (b) CH4                                                 (c) CHCl3                              (d) Cl2

32. The molecule having highest bond energy is:

(a) N–N                                (b) F–F                                  (c) C–C                                  (d) O–O

33. The halide having the highest melting point is:

(a) NaF                                 (b) NaCl                                (c) NaBr                                (d) NaI

34. Born-Haber cycle is used to determine:

(a) Electron affinity         (b) Lattice energy            (c) Crystal energy             (d) All the above

35. The number of s and π-bonds present in pent-1-ene-4- yne is:

(a) 3, 10                                (b) 9, 4                                  (c) 4, 9                                   (d) 10, 3

36. The ion which is not tetrahedral in shape is:

(a) BF4 –                               (b) NH4 +                             (c) [Ni(CN)4]2–                (d) NiCl4 2–

37. The paramagnetic species among the following is:

(a) KO2                                 (b) SiO2                                (c) TiO2                                 (d) BaO2

The paramagnetism of O2 + is due to the presence of an odd electron in the MO:

(a) α*2s                               (b) π2py                               (c) α*2px                             (d) π*2py

38. The correct order of bond angles (smallest first) in H2S, NH3, BF3 and SiH4 is:

(a) H2S < SiH4 < NH3 < BF3                                           (b) NH3 < H2S < SiH4 < BF3

(c) H2S < NH3 < SiH4 < BF3                                          (d) H2S < NH3 < BF3 < SiH4

39. Using MO theory predict which of these species has the shortest bond length?

(a) O2-1                                  (b) O2-2                                                 (c) O2                    (d) O2+2


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