11th class (FSc) chemistry Unit 4 MCQs
51. Crystals formed due to london forces of interaction are:
a. Molecular
b. Ionic
c. Metallic
d. Covalent
52. …… is molecular solid:
a. Diamond
b. NaCl
c. Aluminium nitride
d. CO2 dry ice form
53. London dispersion forces are only forces present among the:
a. Molecule of iodine in solids state
b. Molecules dispersion forces in liquid state
c. Molecule of hydrogen chloride gas
d. Atoms of helium in gaseous state at high temperature
54. Acetone and choloform are soluble in each other due to:
a. Instantaneous dipole
b. Intermolecular hydrogen bonding
c. Ion-dipole interaction
d. All of above
55. NH3 show a maximum boiling point among the hydrides of V-A groupelements due to:
a. Enhanced electronegative character of nitrogen
b. Very small size of hydrogen
c. Pyramidal structure of NH3
d. Lone pair of electrons present on nitrogen
56.When water freezes at 0o C, its density decrease due to:
a. Instantaneous dipole
b. Cubic structure if ice
c. Change of both angles
d. Empty spaces present in structure of ice
57. In order to mention the boiling point of water 110o C the external pressure should be:
a. 765 torr
b. Between structure of ice
c. Any value of bond angles
d. Between 200 toor and 760torr
58. Ionic solids are characterized by:
a. High vapours pressure
b. Low melting points
c. Solubility in polar solvent
d. Good conductivity in solids state
59. Amorphous solids:
a. Have perfect arrangement of atoms
b. Have sharp melting points
c. Can possess small regions of orderly arrangement of atoms
d. Undergo clean cleavage when cut with knife
60. The molecule of CO2 in dry ice from the:
a. Molecular crystals
b. Ionic crystals
c. Any type of crystals
d. Covalent crystals
61. Which is the following is pseudo solid?
a. NaCl
b. CaF2
c. Glass
d. All of these
62. Diamond is bad conductor because:
a. There are no free electrons present in the crystal of diamond to conduct electricity
b. It has tightstructure
c. Is transparent to light
d. It has tight structure
63. DNA molecule doubled stranded, in which two chains of DNA are twisted around each other.
a. Covalent bonds
b. Hydrogen bonds
c. Dative bonds.
d. VAnder waal’s force
64. Correct order of boiling points of the given liquid is:
a. HF>H2O>HCl>HCl
b. H2O>HF>HO>NH3
c. HF<H2O<NH3>HCl
d. HF>H2O<HCl>NH3
65. The coordination number of Na+in NaCl crystal is:
a. 4
b. 6
c. 8
d. 2
66. London dispersion forces are the only forces present among the:
a. Atoms of helium in gaseous state at high temperature
b. Molecules of H2O in liquid state
c. Molecules of solid chlorine
d. Molecules of HCl gas
67. Electrical conductivity of graphite is greater in one direction that in other due to:
a. same as in petrol
b. Isomorphism
c. Negligible
d. Stronger than petrol
68. which one of the following hydrogen bonds is stronger than other:
a. Oδ−−Hδ+. . . . . . Oδ−−Hδ+
b. Nδ−−Hδ+. . . . . . Nδ−−Hδ+
c. Nδ−−Hδ+. . . . . . Oδ−−Hδ+
d. Fδ−−Hδ+. . . . . . Fδ−−Hδ+
69. Ice is less dense than water at:
a. -4oC
b. 0oC
c. 2oC
d. 4oC
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