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4.CHEMICAL BONDING AND MOLECULAR STRUCTURE Single Correct Answer Type 1. The hybrid state of S in SO is similar to that of 3 a) C in C 2 H 2 b) C in C 2 H 4 c) C in CH 4 d) C in CO2 2. The hydration energy of Mg is larger than that of: 2+ a) Al 3+ b) Na + c) Be 2+ d) None of these 3. Number of lone pair (s) in XeOF is/are 4 a) 0 b) 1 c) 2 d) 3 4. Van der Waals’ forces between molecules depend upon: a) Number of electrons b) Charge on nucleus c) Radius of atoms d) All of these 5. XeF is: 6 a) Octahedral b) Pentagonal pyramidal c) Planar d) tetrahedral 6. 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? a) Bond length in NO is greater than in NO + b) Bond length in NO is greater than in NO + c) Bond length in NO is equal to than in NO + d) Bond length is unpredictable 7. An atom with atomic number 20 is most likely to combine chemically with the atom whose atomic number is: a) 11 b) 16 c) 18 d) 10 8. Which has the largest distance between the carbon hydrogen atom? a) Ethane b) Ethene c) Ethyne d) Benzene 9. Length of hydrogen bond ranges from 2.5Å to: a) 3.0 Å b) 2.75 Å c) 2.6 Å d) 3.2 Å 10. If H − X bond length is 2. 00 Å and H − X bond has dipole moment 5. 12×10 , −30 C − m the percentage of ionic character in the molecule will be a) 10% b) 16% c) 18% d) 20% Page| 1
11. Which molecule is planar? a) NH 3 b) CH 4 c) C 2 H 4 d) SiCl 4 12. From the molecular orbital theory, one can show that the bond order in F molecule as 2 a) 2 b) 1 c) 3 d) 4 13. Two ice cubes are pressed over each other until they unite to form one block. Which one of the following forces dominates for holding them together? a) Dipole-dipole interaction b) Van der Waals’ forces c) Hydrogen bond formation d) Covalent attraction 14. Maximum number of covalent bonds between two like atoms can be: a) Three b) Two c) Four d) One 15. When sodium and chlorine react, energy is: a) Released and ionic bond is formed b) Released and covalent bond is formed c) Absorbed and covalent bond is formed d) Absorbed and ionic bond is formed 16. The maximum possible number of hydrogen bonds is a H molecule can participate is 2 O a) 1 b) 2 c) 3 d) 4 17. The element having lowest ionisation energy among the following is: a) 1s 2 , 2s 2 2p 3 b) 1s 2 , 2s 2 2p 6 , 3s 1 c) 1s 2 , 2s 2 2p 6 d) 1s 2 , 2s 2 2p 5 18. Bond energies in NO, NO and are such as + NO − a) NO − > NO > NO + b) NO > NO − > NO + c) NO + > NO > NO − d) NO + > NO − > NO 19. Two type FXF angles are present in which of the following molecules? (X=S, Xe, C) a) SF 4 b) XeF 4 c) SF 6 d) CF 4 20. The bond angle between two hybrid orbitalsis 105°. The percentage of s-character of hybrid orbital is between a) 50 − 55% b) 9 − 12% c) 22 − 23% d) 11 − 12% 21. Which is electron deficient compound? a) C 2 H 4 b) B 2 H 6 c) C 2 H 6 d) NaBH 4 22. CCl is insoluble in water because: 4 a) CCl is non-polar and water is polar 4 b) Water is non-polar and CCl is polar 4 Page| 2
c) Water and CCl both are polar 4 d) None of the above 23. Which of the following is not correct regarding the properties of ionic compounds? a) Ionic compounds have high metling and boiling points b) Their reaction velocity in aqueous medium is very high c) Ionic compounds in their molten and aqueous solutions do not conduct electricity d) They are highly soluble in polar solvents 24. The number of sigma and pi (π) bonds present in benzene respectively are a) 12, 6 b) 6, 6 c) 6, 12 d) 12, 3 25. Which of the following is not tetrahedral? a) BF 4 − b) NH 4 + c) CO3 2− d) SO 4 2− 26. In PCl molecule, P is: 5 a) sp -hybridized 3 b) dsp -hybridized 2 c) ds -hybridized 3 p d) sp -hybridized 3 d 27. The bond angle and % of d-character in SF are 6 a) 120°, 20% b) 90°, 33% c) 109°, 25% d) 90°, 25% 28. Linear combination of two hybridized orbitals, belonging to two atoms and each having one electron leads to: a) Sigma-bond b) Double bond c) Coordinate covalent bond d) Pi-bond 29. In allene structure, three carbon atoms are joined by: a) Three σ-and three π-bonds b) Two σ- and one π-bond c) Two σ-and two π-bonds d) Three π-bonds only 30. Geometry of SiO anion is 4 4− a) Tetrahedral b) Trigonal c) Trihedral d) Pentagonal 31. The carbon atom in graphite is: a) sp -hybridized 2 b) sp -hybridized 3 c) sp-hybridized d) None of these Page| 3
32. Boron cannot form which one of the following anions? a) BF 6 3− b) BH 4 − c) B(OH) 4 − d) BO2 − 33. If the ionic radii of K and are about 1.34 Å each, then the expected values of atomic radii of and + F − K F should be respectively: a) 1.34 and 1.34 Å b) 2.31 and 0.64 Å c) 0.64 and 2.31 Å d) 2.31 and 1.34 Å 34. If Z-axis is the molecular axis, then π-molecularorbitals are formed by the overlap of a) s + p z b) p x + p y c) p z + p z d) p x + p x 35. Which one is the weakest bond? a) Hydrogen b) Ionic c) Covalent d) Metallic 36. The total number of valency electrons for PO ion is: 4 3− a) 32 b) 16 c) 28 d) 30 37. The ratio of σ and π-bonds in benzene is: a) 2 b) 6 c) 4 d) 8 38. The geometry of PF molecule is: 5 a) Planar b) Square planar c) Trigonal bipyramidal d) Tetrahedral 39. Which one of the following linear structure? (I)I (II) 3 − NO2 − (III)I (IV) 3 + SO2 (V)N 3 − a) I, II and III b) I and V c) II, III and IV d) All of these 40. According to MO theory, which of the following lists ranks the nitrogen species in terms of increasing bond order? a) N 2 − < N 2 2− < N 2 b) N 2 − < N 2 < N 2 2− c) N 2 2− < N 2 − < N 2 d) N 2 < N 2 2− < N 2 − 41. The equilateral triangle shape has: a) sp-hybridization b) sp - 2 hybridization c) sp - 3 hybridization d) sp -hybridization 3 d 42. Which of the following has fractional bond order? a) O2 2+ b) O2 2− c) F 2 2− d) H 2 − 43. For which of the following hybridization the bond angle is maximum? a) sp 2 b) sp c) sp 3 d) dsp 2 44. Experiment shows that H has a dipole moment whereas, has not. Point out the structures which 2 O CO2 best illustrate these facts: Page| 4