CBSE Questions for Class 12 Engineering Chemistry The Solid State Quiz 15 - MCQExams.com

An alkali metal has density $$4.5g/{ cm }^{ 3 }$$. It has cubic unit cell with an edge length $$400pm$$. Reaction of $$7.68{ cm }^{ 3 }$$ chunk of the metal with an excess of $$HCl$$ solution gives a colorless gas that occupies $$4.54L$$ at $${0}^{o}C$$ and $$1$$ bar. The unit cell of metal is
  • Simple cubic
  • BCC
  • FCC
  • End-centered
A solid element (monoatomic) exists in cubic crystal. If its atomic radius is $$1.0\mathring { A } $$ and the ratio of packing fraction and density is $$0.1{cm}^{3}/g$$, then the atomic mass of the element is $$\left( { N }_{ A }=6\times { 10 }^{ 23 } \right) $$
  • $$8\pi $$
  • $$16\pi $$
  • $$80\pi $$
  • $$4\pi $$
Iodine molecules are held in the crystal lattice by?
  • London forces
  • Dipole-dipole interactions
  • Covalent bonds
  • Ionic bonds
In $${Na}_{2}O$$ structure
  • $${ O }^{ 2- }$$ ions constitute CCP and $${Na}^{+}$$ ions occupy all the octahedral holes
  • $${ O }^{ 2- }$$ ions constitute CCP and $${Na}^{+}$$ ions occupy all the tetahedral holes
  • $${ O }^{ 2- }$$ ions constitute CCP and $${Na}^{+}$$ ions occupy $$50$$% of tetrahedral holes and $$100$$% octahedral holes
  • $${Na}^{+}$$ ions constitute CCP and $${ O }^{ 2- }$$ ions occupy half of octahedral holes
The yellow colour or $$ZnO$$ and conducting nature produced in heating is due to
  • Metal excess of defects due to interstitial cation
  • Extral positive ions present in an interstitial site
  • Trapped electrons
  • All
Which void is smallest in close packing?
  • tetrahedral
  • octahedral
  • cubic
  • square
Frenkel defect is noticed in 
  • $$AgBr$$
  • $$ZnS$$
  • $$AgI$$
  • All
If the unit cell length of sodium chloride crystal is $$600pm$$, then its density will be
  • $$2.165g/{ cm }^{ 3 }$$
  • $$3.247g/{ cm }^{ 3 }$$
  • $$1.79g/{ cm }^{ 3 }$$
  • $$1.082g/{ cm }^{ 3 }$$
Which of the following defects in the crystals may lower the density?
  • Interstitial defect
  • Vacancy defect
  • Schottky defect
  • Impurity defect
The correct statement(s) for the packing of identical spheres in two dimensions is/are
  • For square close packing, the coordination number is $$4$$
  • For HCP, the coordination number is $$6$$
  • There is only one void per sphere in both, square and HCP
  • HCP is more efficiently packed than square close packing
Potassium hexachloroplatinate (IV), $${K}_{2}[Pt{ Cl }_{ 6 }]$$ adopts anti-fluorite crystal structure. The correct information(s) about ideal $${K}_{2}[Pt{ Cl }_{ 6 }]$$ crystal is/are
  • $${K}^{+}$$ ions occupy all the tetrahedral voids
  • The unit cell is FCC with respect to $$Pt{ Cl }_{ 6 }^{ 2- }$$ ions
  • The coordination number of $$Pt{ Cl }_{ 6 }^{ 2- }$$ ions is $$4$$
  • The coordination number of $$Pt{ Cl }_{ 6 }^{ 2- }$$ ions is $$8$$
Which of the following information(s) is/are incorrect regarding the voids formed in three-dimensional HCP of identical spheres?
  • A tetrahedral void is formed when a sphere of the second layer is present above the triangular void of the first layer
  • All the triangular voids are not covered by the spheres of the second layer
  • Tetrahedral voids are formed when the triangular voids in the second layer lie above the triangular voids in the first layer and the triangular shapes of these voids do not overlap
  • Octahedral voids are formed when the triangular voids in the second layer exactly overlap with similar voids in the first layer
Which of the following has face-centered Bravais lattice?
  • Hexagonal
  • Monoclinic
  • Cubic
  • Orthorhombic
Packing fraction in 2D-hexagonal arrangement of identical spheres is
  • $$\cfrac { \pi }{ 3\sqrt { 2 } } $$
  • $$\cfrac { \pi }{ 3\sqrt { 3 } } $$
  • $$\cfrac { \pi }{ 2\sqrt { 3 } } $$
  • $$\cfrac { \pi }{ 6 } $$
In which of the following crystals, alternate tetrahedral voids are occupied?
  • $$NaCl$$
  • $$ZnS$$
  • $$Ca{F}_{2}$$
  • $${Na}_{2}O$$
The ratio of density of $$NaCl$$ to that of $$KCl$$ is
  • $$1.49$$
  • $$1.17$$
  • $$0.853$$
  • $$1.143$$
Which of the following is/are correct regarding point defects in solids?
  • The density of point defect increases with the increase in rate of crystallization
  • In the formation of point defects, the entropy of system increases but the entropy of the surrounding decreases
  • The density of point defect increases with the increase in temperature
  • All point defects results a decrease in the density of the solid
The volume effectively occupied by a single $$CsCl$$ ion pair in the crystal is?
  • $$48ml$$
  • $$8\times { 10 }^{ -23 }ml$$
  • $$3.2\times { 10 }^{ -22 }ml$$
  • $$2\times { 10 }^{ -23 }ml$$
The correct statement(s) regarding defects in solid is (are)
  • Frenkel defect usually favoured by a very small difference in the sizes of cation and anion
  • Frenkel defect is a dislocation defect
  • Trapping of an electron in the lattice leads to the formation of F-centre
  • Schottky defect have no effect on the physical properties of solids
Which of the following statement(s) is/are incorrect regarding the defects in solids?
  • $$AgBr$$ crystal show both Schottky and Frenkel defect
  • Impurity defect by doping of Arsenic in Silicon results n-type semiconductor
  • Doping in crystal introduces dislocation defect
  • Metal deficient defect can occur with extra anion present in the interstitial voids
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