Page 1 :
1. According to the valence bond theory, when a covalent bond is formed between two reacting atoms, the, potential energy of the system becomes___________, (1) negative, (2) positive, (3) minimum, (4) maximum, Answer: 3, 2. The strongest covalent bond is formed by the overlap of– (If considering for same shell)_________, (1) s and p orbitals, (2) s and s orbitals, (3) p and d orbitals, (4) p and p collateral orbitals, Answer: 1, 3. In a triple bond there is sharing of_________, (1) 3 – electrons, (2) 4 – electrons, (3) Several electrons, (4) 6 – electrons, Answer: 4, 4. Which of the following statements regarding covalent bond is not true?, (1) The electrons are shared between atoms, (2) The bond is non-directional, (3) The strength of the bond depends upon the extent of overlapping, (4) The bond formed may or may not be polar, Answer: 2, 5. Which of the following is incorrect about hybridization?, (1) The concept of hybridization is not applied to isolated atoms., (2) Hybridization is the mixing of at least two non-equivalent atomic orbitals., (3) The number of hybrid orbitals generated is more than the number of pure atomic orbitals that participate in, the hybridization process., (4) Hybridization requires an input of energy., Answer: 3, 6. Which condition favors the bond formation______, (1) Maximum attraction and maximum potential energy, (2) Minimum attraction and minimum potential energy, (3) Minimum potential energy and maximum attraction, (4) None of the above, Answer: 3, 7. The F – F bond is weak because____________, (1) The repulsion between the nonbonding pairs of electrons of two fluorine atoms is large, (2) The ionization energy of the fluorine atom is very low, (3) The length of the F-F bond much larger than the bond lengths in other halogen molecules, (4) The F-F bond distance is small and hence the internuclear repulsion between the two F atoms is very low., Answer: 1, 8. The bond length does not affected by________, (1) Electron affinity, (2) Bond order, (3) Hybridisation, (4) Resonance
Page 2 :
Answer: 1, 9. In all structure three carbon atoms are joined by________, (1) Three sigma bonds and three pi bonds, (2) Two sigma bonds and one pi bond, (3) Two sigma bonds and two pi bonds, (4) Three pi bonds only, Answer: 3, 10. In the protonation of NH3 molecule, the following statement is true________, (1) A covalent bond is formed, (2) Hydrogen bond is formed, (3) Hybridization state of N is changed, (4) Shape of NH3 molecule is changed, Answer: 4, 11. The shape of sulphate ion is_____, (1) Hexagonal, (2) Square planar, (3) Trigonal bipyramidal, (4) Tetrahedral, Answer: 4, 12. Among the following element group number is not equals to valence electrons___________, (1) Na, (2) N, (3) Ne, (4) None, Answer: 3, 13. Which of the following halides has the highest melting point________, (1) NaCl, (2) KCl, (3) NaBr, (4) NaF, Answer: 4, 14. CCl4 is more covalent than LiCl because__________, (1) There is more polarization of Cl in CCl4, (2) There is more polarization of Cl in LiCl, (3) CCl4 has more weight, (4) None of above, Answer: 1, 15. As compared to covalent compounds electrovalent compounds generally possess___________, (1) High m.p. and high b.p., (2) Low m.p. and low b.p., (3) Low m.p. and high b.p., (4) high m.p. and low b.p., Answer: 1, 16. Conditions for ionic bond formation is / are________, (a) Small cation, large anion, (b) Low IP of cation, high electron affinity of anion, (c) Large cation, small anion and less charge, (d) Less lattice energy, Correct answer is:
Page 3 :
(1) a, d, (2) b, c and d, (3) b and c, (4) a, b, Answer: 3, 17. Capacity of solvent to neutralize charge on ionic compound is called________, (1) Solvation energy, (2) Dielectric constant, (3) Dipole moment, (4) Solubility, Answer: 2, 18. The force responsible for dissolution of ionic compound in water is_________, (1) Dipole - dipole forces, (2) Ion - dipole force, (3) Ion - ion force, (4) Hydrogen bond, Answer: 2, 19. Born Haber cycle is mainly used to determine________, (1) Lattice energy, (2) Electron affinity, (3) Ionization energy, (4) Electronegativity, Answer: 1, 20. An ionic compound A+ B– is most likely to be formed when________, (1) Ionization energy of A is low, (2) Electron affinity of B is high, (3) Electron affinity of B is low, (4) Both (1) and (2), Answer: 4, 21. The pair of elements which on combination are most likely to form an ionic compound__________, (1) Na and Ca., (2) K and O, (3) O and Cl, (4) Al and I., Answer: 2, 22. The electrovalency of the element is equal to the___________, (1) number of electrons lost, (2) number of electrons gained, (3) number of electrons transferred, (4) Number of electrons lost or gained by the atom of the element during the formation of ionic ions compound, Answer: 4, 23. Ionic bond formation involves________, (1) Elimination of protons, (2) Sharing of electrons, (3) Overlapping of orbitals, (4) Formation of octets, Answer: 4, 24. The hydration of ionic compounds involves____________, (1) Evolution of heat
Page 4 :
(2) Weakning of attractive forces, (3) Dissociation into ions, (4) All, Answer: 4, 25. Two ice cubes are pressed over each other until they unite to form one block. The force mainly responsible for, holding them together is___________, (1) van der Waals force, (2) dipole-dipole interaction, (3) H bonding, (4) covalent bonding, Answer: 3, 26. The vapor pressure of o-nitrophenol at any given temperature is predicted to be______, (1) higher than that of p-nitrophenol, (2) lower than that of p-nitrophenol, (3) same as that of p-nitrophenol, (4) higher or lower depending upon the size of the vessel, Answer: 1, 27. Which is the weakest among the following types of bonds?, (1) Debye force, (2) Metallic bond, (3) Dipole-dipole bond, (4) Hydrogen bond, Answer: 1, 28. The boiling point of p-nitrophenol is higher than that of o-nitrophenol because__________, (1) NO2 group at p-position behaves in a different way from that at o-position, (2) intramolecular hydrogen bonding exists in p-nitrophenol, (3) there is intermolecular hydrogen bonding in p-nitrophenol, (4) p-nitrophenol has a higher molecular weight than o-nitrophenol, Answer: 3, 29. In which molecule the Vander Waals force (dispersion force) is likely to be the most important in determining, the m.pt. and b.pt____________, (1) Br2, (2) CO, (3) H2S, (4) HCl, Answer: 1, 30. Covalent-molecules are usually held in a crystal structure by_________, (1) Dipole-dipole attraction, (2) Electrostatic attraction, (3) Hydrogen bond, (4) Van-der waal's attraction, Answer: 4, 31. In solid argon the atoms are held together_______, (1) by ionic bonds, (2) by hydrogen bonds, (3) By vander-waals forces, (4) By hydrophobic bonds, Answer: 3, 32. Which of the following is incorrect regarding the MO theory?
Page 5 :
(1) The number of molecular orbitals formed is always equal to the number of atomic orbitals combined., (2) The more stable the bonding molecular orbital, the less stable the corresponding antibonding molecular orbital., (3) In a stable molecule, the number of electrons in bonding molecular orbitals is always equal to that in antibonding, molecular orbitals., (4) Like an atomic orbital, each molecular orbital can accommodate up to two electrons with opposite spins in, accordance with the Pauli exclusion principle., Answer: 3, 33. The diamagnetic molecule is_________, (1) Super oxide ion, (2) Oxygen molecule, (3) Carbon molecule, (4) Unipositive ion of nitrogen molecule, Answer: 3, 34. Carbon tetrachloride has no net dipole moment because of_________, (1) Similar electron affinity of C and Cl, (2) its regular tetrahedral geometry, (3) its planar geometry, (4) Similar sizes of C and Cl atoms, Answer: 2, 35. Which compound has the weakest bond__________, (1) Diamond, (2) Neon (solid), (3) KCl, (4) water (ice), Answer: 2, 36. When p-character of hybridised orbital (formed by s and p orbitals) increases. Then the bond angle_______, (1) Decreases, (2) Increases, (3) Becomes twice, (4) Remains unaltered, Answer: 1, 37. Strongest hydrogen bond is shown by______, (1) Water, (2) Ammonia, (3) Hydrogen fluoride, (4) Hydrogen sulfide, Answer: 3, 38. Density of ice is less than that of water because of________, (1) presence hydrogen bonding, (2) crystal modification of ice, (3) open porous structure of ice due to hydrogen bonding, (4) different physical states of these, Answer: 3, 39. Which of the following statement is true regarding H-bond_________, (1) it is a directional bond, (2) bond strength is similar to O – H bond, (3) it is attraction between hydrogen and, electronegative atom like as F, O, N, (4) it does not require minimum one lone pair of electron at electronegative atom.
Page 6 :
Answer: 3, 40. Property of the alkaline earth metals that increases with their atomic number_______, (1) Electronegativity, (2) Solubility of their hydroxides in water, (3) Solubility of their sulphates in water, (4) Ionization energy, Answer: 2, 41. Predict the correct order among the following________, (1) lone pair- lone pair> lone pair - bond pair > bond pair - bond pair, (2) lone pair - lone pair> bond pair - bond pair> lone pair - bond pair, (3) bond pair - bond pair> lone pair - bond pair> lone pair - lone pair, (4) lone pair - bond pair> bond pair - bond pair> lone pair - lone pair, Answer: 1, 42. The boiling point of methanol is greater than that of methylthiol because________, (1) There is intramolecular hydrogen bonding in methanol and intermolecular hydrogen bonding in methyl thiol, (2) There is intermolecular hydrogen bonding in methanol and no hydrogen bonding in methylthiol, (3) There is no hydrogen bonding in methanol and intermolecular hydrogen bonding in methylthiol, (4) There is intramolecular hydrogen bonding in methanol and no hydrogen bonding in methylthiol, Answer: 2, 43. The electronegativity difference between N and F is greater than that between N and H yet the dipole mement, of NH3 (1.5 D) is larger than that of NF3 (0.2 D). This is because__________, (1) in NH3 the atomic dipole and bond dipole are in the opposite directions whereas in NF3 these are in the same, direction, (2) in NH3 as well as in NF3 the atomic dipole and bond dipole are in the same direction, (3) in NH3 the atomic dipole and bond dipole are in the same direction whereas in NF3 these are in opposite, directions, (4) in NH3 as well as NF3 the atomic dipole and bond dipole are in opposite directions, Answer: 3
