Q.1. Which of the following statements about amorphous solids is incorrect ?

(a) They melt over a range of temperature
(b) They are anisotropic
(c) There is no orderly arrangement of particles
(d) They are rigid and incompressible

Answer

Ans. (b) Amorphous solids are isotropic, because these substances show same properties in all directions.

Q.2. Which of the following statement is not true about amorphous solids ?
(a) On heating they may become crystalline at certain temperature.
(b) They may become crystalline on keeping for long time.
(c) Amorphous solids can be moulded by heating.
(d) They are anisotropic in nature.

Answer

Ans. (d)

Q.3. Which of the following is not a characteristic property of solids?
(a) Intermolecular distances are short.
(b) Intermolecular forces are weak.
(c) Constituent particles have fixed positions.
(d) Solids oscillate about their mean positions.

Answer

Ans. (b) Intermolecular forces are strong in solids.

Q.4. Most crystals show good cleavage because their atoms, ions or molecules are
(a) weakly bonded together
(b) strongly bonded together
(c) spherically symmetrical
(d) arranged in planes

Answer

Ans. (d) Crystals show good cleavage because their constituent particles are arranged in planes.

Q.5. The coordination number of Y will be in the XY types of crystal:
(a) 6
(b) 8
(c) 12
(d) 4

Answer a

Q.6. Which of the following is not a crystalline solid?
(a) KCl
(b) CsCl
(c) Glass
(d) Rhombic S

Answer

Ans. (c) Glass is amorphous solid.

Q.7. Which of the following is an amorphous solid ?
(a) Graphite (C)
(b) Quartz glass (SiO2)
(c) Chrome alum
(d) Silicon carbide (SiC)

Answer

Ans. (b)

Q.8. “Crystalline solids are anisotropic in nature. What is the meaning of anisotropic in the given statement?
(a) A regular pattern of arrangement of particles which repeats itself periodically over the entire crystal.
(b) Different values of some of physical properties are shown when measured along different directions in
the same crystals.
(c) An irregular arrangement of particles over the entire crystal.
(d) Same values of some of physical properties are shown when measured along different directions in the same crystals.

Answer

Ans. (b) Crystalline solids are anisotropic in nature that is some of their physical properties like electrical resistance or refractive index show different values when measured along different directions in the same crystals.

Q.9. A crystalline solid
(a) changes abruptly from solid to liquid when heated
(b) has no definite melting point
(c) undergoes deformation of its geometry easily
(d) has an irregular 3-dimensional arrangements

Answer a

Q.10. Which of the following is not a characteristic of a crystalline solid ?
(a) Definite and characteristic heat of fusion.
(b) Isotropic nature.
(c) A regular periodically repeated pattern of arrangement of constituent particles in the entire crystal.
(d) A true solid

Answer

Ans. (b)

Q.11. Which of the following is not a crystalline solid?
(a) KCl
(b) CsCl
(c) Glass
(d) Rhombic S

Answer

Ans. (c) Glass is amorphous solid.

Q.12. Which one of the following is non-crystalline or amorphous?
(a) Diamond
(b) Graphite
(c) Glass
(d) Common Salt

Answer

Ans. (c) Glass

Q.13. In Zinc blende structure
(a) zinc ions occupy half of the tetrahedral sites
(b) each Zn2- ion is surrounded by six sulphide ions
(c) each S2- ion is surrounded by six Zn2+ ions
(d) it has fee structure

Answer

Ans. (c) each S2- ion is surrounded by six Zn2+ ions

Q.14. A unit cell of BaCl2 (fluorite structure) is made up of
(a) four Ba2+ ions and four Cl– ions
(b) four Ba2- ions and eight Cl– ions
(c) eight Ba² ions and four Cl– ions
(d) four Ba² ions and six Cl– ions

Answer

Ans. (b) four Ba2- ions and eight Cl– ions

Q.15. Alkali halides do not show Frenkel defect because
(a) cations and anions have almost equal size
(b) there is a large difference in size of cations and anions
(c) cations and anions have low coordination number
(d) anions cannot be accommodated in voids

Answer

Ans. (a) cations and anions have almost equal size

Q.16. The fraction of the total volume occupied by the atoms present in a simple cube is
(a) π/4
(b) π/6
(c) π/3√2
(d) π/4√2

Answer

Ans. (b) π/6

Q.17. Edge length of unit cell of chromium metal is 287 pm with bcc arrangement. The atomic radius is of the order
(a) 287 pm
(b) 574 pm
(c) 124.27 pm
(d) 143.5 pmAnswer

Answer

Ans. (c) 124.27 pm

Q.18. The edge length of fee cell is 508 pm. If radius of cation is 110 pm, the radius of anion is
(a) 110 pm
(b) 220 pm
(c) 285 pm
(d) 144 pm

Answer

Ans. (d) 144 pm

Q.19. The density of a metal which crystallises in bcc lattice with unit cell edge length 300 pm and molar mass 50 g mol-1 will be
(a) 10 g cm-3
(b) 14.2 g cm-3
(c) 6.15 g cm-3
(d) 9.3 2 g cm-3

Answer

Ans. (c)

Q.20. p-type semiconductors are formed When Si or Ge are doped with
(a) group 14 elements
(b) group 15 elements
(c) group 13 elements
(d) group 18 elements

Answer

Ans. (c)

Q.21. Which of the following conditions favours the existence of a substance in the solid state?
(a) High temperature
(b) Low temperature
(c) High thermal energy
(d) Weak cohesive forces

Answer a

Q.22. How many lithium atoms are present in a unit cell with edge length 3.5 Å and density 0.53 g cm-3? (Atomic mass of Li = 6.94):
(a) 2
(b) 1
(c) 4
(d) 6

Answer b

Q.23. The distance between Na– and CL– ions in NaCl with a density 2.165 g cm-3 is
(a) 564 pm
(b) 282 pm
(c) 234 pm
(d) 538 pm

Answer b

Q.24. An element with atomic mass 100 has a bcc structure and edge length 400 pm. The density of element is
(a) 10.37 g cm-3
(b) 5.19 g cm-3
(c) 7.29 g cm-3
(d) 2.14 g cm-3

Answer b

Q.25. Fe3O4 (magnetite) is an example of
(a) normal spinel structure
(b) inverse spinel structure
(c) fluoride structure
(d) anti fluorite structure

Answer b

Q.26. Which of the following crystals does not exhibit Frenkel defect?
(a) AgBr
(b) AgCl
(c) KBr
(d) ZnS

Answer c

Q.27. What type of stoichiometric defect is shown by ZnS?
(a) Schottky defect
(b) Frenkel defect
(c) Both Frenkel and Schottky defects
(d) Non-stoichiometric defect

Answer b

Q.28. NaCl type crystal (with coordination no. 6 : 6) can be converted into CsCl type crystal (with coordination no. 8 : 8) by applying
(a) high temperature
(b) high pressure
(c) high temperature and high pressure
(d) low temperature and low pressure

Answer b

Q.29. How many chloride ions are surrounding sodium ion in sodium chloride crystal ?
(a) 4
(b) 8
(c) 6
(d) 12

Answer c

Q.30. In NaCl structure
(a) all octahedral and tetrahedral sites are occupied
(b) only octahedral sites are occupied
(c) only tetrahedral sites are occupied
(d) neither octahedral nor tetrahedral sites are occupied

Answer b

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