# Solid State

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Solid State preparation for boards

## Content

CBSE Question Bank on
THE SOLID STATE
1. An element occurs in bcc structure. How many atoms are present in its unit cell? [1997]
2. What causes the conduction of electricity by semiconductors ? [SP 1997]
3. A cubic solid is made of two elements P and Q. Atoms Q are at corners of the cube
and P at the body-centre. What is the formula of the compound ? What are the
coordination numbers of P and Q ? [1997D]
4. Copper crystallizes in face-centered cubic lattice and has a density of 8.930 g/cm3 at
293 K. Calculate the radius of copper atom. (At. mass of Cu = 63.55 u) [1997D]
5. An element occurs in bcc structure. It has a cell edge length of 250 pm. Calculate its
molar mass if its density is 8.0 g/cm3 .
6. Metallic gold crystallises in a fcc lattice and has a density of 19.3 g/cm3 . Calculate
the radius of gold atom. (At. mass of gold = 197 u)
[1997AI]
7. What are non-stoichiometric compounds ? [1998AI]
8. What may be the difference between Phosphorus doped and Gallium doped
semiconductors ? [1998F]
9. Why is Frenkel defect found in AgCl ? [1999AI]
10. Name the two types of crysal imperfections. [1999AI]
11. Why does a pure silicon which is an insulator, behave as a semiconductor on
heating ? [1999D]
12. How many atoms are there in a unit cell of a metal crystallizing in fcc structure? [1999]
13. An element A crystallises in fcc structure, 208 g of this element has 4.283 × 1024 atoms.
If edge length of the unit cell of this element is 408 pm, calculate its density. [1999AI]
14. An element crystallizes in fcc structure. Its density is 7.9 g/cm3 . 208 g of this element
has 4.283 × 1024 atoms. Calculate the edge length of the unit cell. [1999D]
15. Which point defect lowers the density of ionic crystals ? [2000AI]
16. Determine the type of cubic lattices to which the iron crystal belongs if its cell has an
edge length of 268 pm and the density of iron crystal is 7.86 g/cm3 .
(At. weight of Fe = 56 g/mol)
[2000D]
17. An element exists in bcc structure with a cell edge of 288 pm. If the density of the
element is 7.2 g/cm3 , what is atomic mass of the element ? [2000AI&F]
18. What is the difference between ferromagnetic and ferrimagnetic substances ? [2001D]
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19. Why does Frenkel defect not change the density of AgCl crystal ? [2001AI]
20. What other elements may be added to silicon to make electrons available for the
conduction of electric current ?
[2001D]
21. An element A crystallizes in fcc structure. 200 g of this element has 4.12 × 1024
atoms. The density of A is 7.2 g/cm3 . Calculate edge length of unit cell. [2001AI]
22. Sodium crystallizes in the cubic lattice and the edge length of the unit cell is 430 pm.
Calculate the number of atoms in a unit cell.
(At. mass of Na = 23.0 and density = 0.9623 g/cm3 )
[2001AI]
23. Lithium metal crystal has body centered cubic structure. Its density is 0.53 g/cm3
and its molar mass is 6.94 g/mol. Calculate the volume of unit cell of lithium
metal.
[2001AI]
24. If NaCl crystals are doped with 2 × 10-3 mol per cent of SrCl2, calculate the cation
vacancies per mole.
[2001D]
25. Unit cell of an element (atomic mass 108 u and density 10.5 g/cm3 ) has an edge
length 409 pm. Deduce the type of crystal lattice.
[2001F]
26. An element having bcc structure has atomic mass 50 u and density 6.81 g/cm3 .
Calculate the edge length of the unit cell.
[2001F]
27. State the difference between Schottky and Frenkel defects. Which of the two changes
the density of the solid ?
[2002AI]
28. Mention one property which is caused due to the presence of F-centre in a solid.
[2003D]
29. Which solid is likely to be the best material for converting sunlight into electricity ?
[2003F]
30. In an alloy of gold and cadmium, gold crystallizes in cubic structure occupying the
corners only and cadmium fits into the face centre voids. What is quantitative
composition of the alloy ?
[2003D]
31. What is the difference between glass and quartz, through both contain SiO44- units ?
[2003D]
32. Name on solid in which both Frenkel and Schottky defects occur. [2003AI]
33. What is the effect of Frenkel defect on electrical conductivity of the solid ? [2003AI]
34. An element occurs in bcc structure with cell edge 300 pm. The density of the element
is 5.2 g/cm3 . How many atoms of the element does 200 g of the element contain ?
[2003D]
35. The density of chromium ion metal is 7.2 g/cm3. If the unit cell has edge length of
289 pm, determine the type of unit cell. (At. mass of Cr = 52 u)
[2003AI]

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36. Name a substance which on addition to AgCl causes cation vacancy in it. [2004D]
37. What makes alkali metal halides sometimes coloured, which are otherwise colourless ?
[2004D]
38. Define the term ‘amorphous’.
[2004AI]
39. Which point defect lowers the density of a crystal ?
[2004AI]
40. What is coordination number of a metal atom in ccp structure ?
[2004F]
41. Why is common salt sometime yellow instead of being pure white ? [2004 F]
42. Why are Frenkel defects not found in pure alkali halides ? [2004D]
43. What happens when ferrimagnetic Fe3O4 is heated at 850 K and why ? [2004AI]
44. How can a ferromagnetic substance be changed to paramagnetic one ? [2004AI]
45. What is the nature of crystal defect produced when sodium chloride is doped with
MgCl2 ?
[2004D&2005D]
46. Name an element with which germanium can be doped to produce an n-type
semiconductor. [2005F]
47. What happens when a ferromagnetic substance is subjected to high temperature ?
[2005AI]
48. Why is potassium chloride sometimes violet instead of pure white ? [2005AI]
49. How many atoms can be assigned to its unit cell if an element forms (i) a body
centred cubic cell and (ii) a face centred cubic cell ? [2005AI]
50. What is the maximum possible coordination number of an atom in an hcp crystal
structure of an element ?
[2005D]
51. Aluminium crystallizes in a cubic closed-packed structure. Its metallic radius is 125 pm
(a) What is the length of the side of the unit cell ?
(b) How many unit cells are there in 100 cm3 of aluminium ?
[2005D]
52. (a) Determine the type of cubic lattice to which a given crystal belongs if it has edge
length of 290 pm and density is 7.80 g/cm3
(molecular mass = 56 g/mol)
(b) Why does zinc oxide exhibit enhanced electrical conductivity heating ? [2005D]
53. What is the effect of Schottky a Frenkel defects on the density of crystalline solids ?
[2005AI&2006AI]
54. A cubic solid is made of two elements X and Y. Atoms Y are at the corners of the
cube and X at the body centre. What is the formula of the compound ? [2006D]
55. Name the non-stoichiometric point defect responsible for colour in alkali halides.
[2006AI]
56. Name an element with which silicon can be doped to give a p-type semiconductor.
[2006F]
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57. Name the crystal defect which lowers the density of an ionic crystal. [2006D]
58. What makes the crystal of KCl appear sometime violet ? [2006AI]
59. Copper is conducting as such while sulphate is conducting only in molten state or
in aqueous solution. Give reasons.
[2006AI]
60. Explain n type semiconductors with examples.
[2006D]
61. (a) With reference to crystal structure, what is meant by coordination number ?
(b) What is the coordination number of atoms
(i) in a cubic close packed structure.
(ii) in a body-centred cubic structure ?
[2006D]
62. What is semiconductor ? Describe two main types of semiconductors giving examples
and their distinctive features.
[2006AI]
63. Calculate the efficiency of packing in case of a metal crystal for simple cubic. [2006AI]
64. What is the coordination number of a rock salt type structure. [2007F]
65. Name an element with which silicon can be doped to give n-type semiconductors.
[2007F]
66. Explain with suitable examples : (i) Paramagnetism
(ii) Frenkel defect in crystals
[2007D]
67. Assign reasons for the following :
(i) Phosphorus doped silicon is semiconductor.
(ii) Schottky defect lowers the density of a solid.
(iii) Some of very old glass objects appears slightly milky instead of being pure
transparent.
[2007AI]
68. What type of substances exhibits antiferromagnetism ?
[2008D]
69. How would you account for the following ?
(ii) Impurity doped silicon is a semiconductor.
[2008D]
70. Explain the following properties giving suitable examples :
(i) Ferromagnetism
(ii) Paramagnetism
(iii) Ferrimagnetism
71. Silver crystallizes in an fcc lattice. The edge length of a unit cell is 4.077 × 10-8 cm.
And its density is10.5 g/cm3. Calculate the atomic mass of silver. [2008AI]
72. What type of alignment in crystals make them ferromagnetic ? [2008F]
73. Explain with suitable examples : Frenkel defect and F-centres.
[2008F]
74. Iron has body centred cubic unit cell with a cell edge of 286.65 pm. The density of iron
Is 7.87 g/cm3 . Use this information to calculate Avogadro number.
(Atomic weight of Fe = 56 g/mol)
[2009D]

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75. Silver crystallizes with face-centred cubic unit cells. Each side of the unit cell has a
Length of 409 pm. What is the radius of an atom of silver ?
[2009AI]

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