1. ABABA......... represents an arrangement of layers called-
(a) hexagonal closed packing
(b) cubic closed packing
(c) body centred cubic packing
(d) fluorite close packing
2. The number of molecules per unit cell which crystalizes in the form of end face centred (monoclinic) lattice with a molecule at each lattice site
(a) 1 (b) 2
(c) 4 (d) 6
3. In diamond the coordination no. of carbon is-
(a) 4 and its unit cell has 8 carbon atoms.
(b) 4 and its unit cell has 6 carbon atoms
(c) 6 with 4 carbon atoms in unit cell
(d) 4 with 4 carbon atoms in unit cell
Hint : The space lattice of Diamond is fcc
4. Which of the following crystals does not have 8 : 8 coordination.
(a) NH4Cl (b) AlFe
(c) MnO (d) NH4Br
5. The bond length and bond angles in molecules in the solid state are calculated by x-ray differaction technique because
x-rays are scattered by -
(a) Nucleus (b) Protons only
(c) Neutrons only (d) Electrons only
6. Mark the incorrect statement
(a) In hcp and ccp the sphere is in contact with 6 spheres
of its own layer.
(b) In both hcp and ccp the sphere has 3 spheres above
it and 3 below it.
(c) In both hcp and ccp the coordination no. is 12.
(d) In inverse spinel (e.g. magnetite, Fe3O4) only
dipositive ions occupy octohedral voids while
tripositive ions occupy tetrahedral voids.
7. A compound formed by elements A and B crystallises in cubic structure, in which atoms of A are at the corners while
that of B are at the face centre. The formula of the compound is -
(a) AB3 (b) AB
(c) A3B (d) None of these
8. Na atom crystallises in bcc lattice with cell edge (a) = 4.29A° The radius of Na atom is -
(a) 18.6A° (b) 1.86A°
(c) 1.86 pm (d) 1.860 pm
9. Pick out the incorrect statement -
(a) NaCl structure transform to CsCl structure on heating
(b) In CaF2 structure each F- ion is coordinated by 4 Ca++ ions and each Ca++ ion is coordinated by 8F- ions.
(c) NaCl has 6:6 coordination, while CsCl is with 8:8 coordination
(d) In Na2O each oxide ion is coordinated by 8 Na+ ions and each Na+ ion by 40 oxide ions
10. NaCl is doped with 2 x 10-3 mole % of SrCl2. The concentration of cation vacancies is -
(a) 6.02 x 108per mol (b) 12.04 x 1018 per mol
(c) 3.01 x 1018 per mol (d) 12.04 x 1020per mol
11. CaO and NaCl have the same crystal structure and nearly the same ionic radii. If x is the lattice energy of NaCl, the
lattice energy of CaO is very nearly :
(a) 2 x (b) x
(c) 4x (d) x / 2
12. Which of the following expression is correct for a CsCl unit cell with lattice parameter a.
13. Which of the following crystals have 6:6 coordination?
(a) NH4l (b) MnO
(c) ZnS (d) None
14. Match list I with list II and select the correct answer by using the codes given below :
List I (Shape) List II (Radius ratio)
(A) Planer triangle 1 0.732
(B) Square Planer 2 0.225
(C) Body Centred cubic 3 0.115
(D) Tetrahedral 4 0.414
Codes A B C D
(a) 3 4 1 2
(b) 3 2 1 4
(c) 2 1 4 3
(d) 1 3 4 2
15. Calculate the ionic radius of a Cs+ion assuming the cell edge length for CsCl is 0.4123 nm and that the ionic radius of a Cl- ion is 0.181 nm.
(a) 0.176 nm (b) 0.231 nm
(c) 0.358 nm (d) 0.116 nm
16. Because of anisotropy -
(a) Mica cleaves into long, rod like peices and asbestos
cleaves into thin sheets.
(b) Mica as well as asbestos cleaves into thin sheets.
(c) Mica cleaves into thin sheets and asbestos cleaves
into long rod like peices
(d) Mica as well as asbestos cleaves into long rod like
17. Which of the following crystals has 4:4 coordination ?
(a) HgS (b) NH4F
(c) NaCl (d) None
18. The hcp and ccp structure for a given element would be expected to have -
(a) the same alignment of layers.
(c) the same density
(c) the same packing fraction
(d) All the above
19. Which of the following statements is correct -
(a) The coordination number of each ion in a CsCl
crystal is 9.
(b) A metal that crystallizes in a bcc structure has a
coordination number of 12.
(c) A unit cell an ionic crystal shares some of its ions
with other unit cells.
(d) The length of unit cell in NaCl is 552 pm withrNA= 95
pm and rCL= 181 pm
20. Iron crystalizes in a bcc system with a lattice parameter of 2.861 A°. Calculate the density of Iron in it (at wt. of iron = 56, NA = 6.02 x 1023 permole)
(a) 7.92 g/ml (b) 8.96 gm/ml
(c) 2.78 gm/ml (d) 6.72 gm/ml
21. Which of the following statements is incorrect ?
(a) A substitutional solid solution is one in which atoms of the solute metal occupy some locations that solvent metal atoms are expected to occupy
(b) An interstitial solid solution is one in which the solute atoms occupy the interstices between the solvent atoms.
(c) An intermediate compound is a compound formed between metals and metalloids.
(d) Cu3Zn is an intermetallic compound.
22. MZXhave a structure closely related to that of fluorite it is actually reverse of fluorite structure hence called ANTIFLUORITE structure. In such a structure-
(a) Smaller cations occupy the position of fluoride ion and larger anions that of Ca++ ions.
(b) Larger cations occupy the position of F- ions and smaller anions that of ca++ ions.
(c) Each F- is surrounded by 4 Ca++ in a tetrahedral arrangement
(d) F- ions occupy all the 8 octohedral voids.
23. The incorrect statements for sphalerite, a form of ZnS is-
(a) It structure is similar to diamond except that alternate atoms are Zn and S.
(b) Because the S- is larger than the Zn ion only 6 rather than 4 or 8 sulfide ions can be packed around a Znion.
(c) As s- is larger than Zn++ only 4 rather than 6 or 8 s- can be packed around Zn++
(d) ZnS is a polar covalent compound.
24. The fluorite structure shows 8:4 coordination, which of the following lattices have fluorite like structure -
(a) SrCl2 (b) BaF2
(c) ThO2 (d) All the above
25. In an NaCl structure all the -
(a) Octohedral voids are unoccupied
(b) Tetrahedral voids are unoccupied
(c) Octohedral as well as tetrahedral voids occupied
(d) Octohedral as well as tetrahedral voids unoccupied.
26. Which of following structures have layered lattices-
(a) Diamond (b) Ice
(c) Cadmium lodide (d) All
27. T1O2 (rutile) shows 6:3 coordination. The solid having rutile like structure among the following is -
(a) ZnS (b) KCl
(c) SnO2 (d) None of the above
28. The statement correct for rock salt structure is -
(a) The tetrahedral voids are larger than octohedral voids
(b) The tetrahedral voids are unoccupied while
octohedral voids are occupied by cations.
(c) The radius ratio is 0.732
(d) The radius ratio is 0.999.
29. How many octohedral voids are there per sphere in a ccp structure.
(a) 4 (b) 2
(c) 1 (d) 6
30. Which of the following crystals shows 4:2 coordination?
(a) CaF2 (b) SiO2
(c) PbO2 (d) None of the above
31. The coordination no. of fcc structure for metals is 12, since-
(a) each atom touches 4 others in same layer, three in layer above and 3 in layer below.
(b) each atom touches 4 others in same layer, 4 in layer above and 4 in layer below-
(c) Each atom touches 6 others in same layer, 6 in layer above and 6 in layer below.
(d) Each atom touches 3 atoms in the same layer, 6 in layer above and 6 in layer below.
32. Amorphous solids may be classified as -
(a) Isotropic and super cooled liquids
(b) Anisotropic and super cooled liquids
(c) Isoenthalpic and superheated liquids
(d) Isotropic and superheated solids
33. Correct statement for ccp is -
(a) each octohedral void is surrounded by 6 spheres & each sphere is surrounded by 30 octohedral voids.
(b) each octohedral void is surrounded by 6 sphere & each sphere is surrounds by 6 octohedral voids.
(c) each octohedral void is surrounded by 6 spheres and each sphere is surrounded by 8 octohedral void
(d) each octohedral void is surrounded by 6 sphere and each sphere is surrounded by 12 octohedral voids.
34. If hcp and ccp structures are made up of spheres of equal size, the volume occupied per sphere is (given r=radius of sphere)
(a) 1.33 r3 (b) 5.66 r3
(c) 2.66 r3 (d) 7.40 r3
35. F - centres are -
(a) The electrons trapped in anionic vacancies
(b) The electrons trapped in cation vaccancies
(c) Non equivalent sites of stoichiometric compounds
(d) All of the above.
36. Mark the incorrect relation -
(a) No. of octohedral voids (In hcp, ccp) = No. of atoms present in closed packed arrangement
(b) No. of tetrahedral voids = 2 x no. of octohedral voids
(c) ABAB ..... is cubic close packing and ABC ABC .... hexagonal close packing
(d) Radius of octohedral void r = 0.414 R
37. It was found that parazoxyanide melts at 389 K to give a turbid non uniform liquid but at 408 K, it melts to form clear uniform isotropic liquid. What type of crystal is being described.
(a) Molecular crystal (b) covalent crystal
(c) Liquid crystal (d) H-bonded crystal
38. Li metal has a bccp structure. Its density is 0.53g per cm3 and its atomic mass is 6.94 gm per mol calculate the edge length of a unit cell of Li metal
(a) 153.6 pm (b) 351.6 pm
(c) 527.4 pm (d) 263.7 pm
39. A metal crystalizes in 2 cubic phases i.e., fcc and bcc whose unit cell lengths are 3.5A° and 3.0A° respectively. The ratio of their densities is -
(a) 3.12 (b) 2.04
(c) 1.46 (d) 0.72
40. In the x-ray differaction of a set of crystal planes having d equal to 0.18 nm a first order reflection is found to be at an angle of 22°. The wave length of x-ray is - (given sin 22° = 0.208
(a) 0.0749 nm (b) 0.0374 nm
(c) 0.749 nm (d) None of these
41. For a given crystal the lattice parameter a is 318 pm. The d-spacing for a (III) plane is -
(a) 225 pm (b) 184 pm
(c) 318 pm (d) 390 pm
42. Which of the following statements are correct in context of point defects in a crystal ?
(a) AgCl has anion Frenkel defect and CaF2has Schottky defects.
(b) AgCl has cation frenkel defects and CaF2has anion frenkel defect.
(c) AgCl as well as Ca2 have anion frenkel defects
(d) AgCl as well as CaF2has schottky defects.
43. LiBH4 Crystalizes in orthorhombic system with 4 molecules per unit cell. The unit cell dimensions are a = 6.8 A°b=4.4 A° and ?c = 7.2A°. If the molar mass is 21.76 the density is -
(a) 0.6708 gm/cm3. (b) 1.6708 gm/cm3.
(c) 2.6708 gm/cm3. (d) All of the above
44. NaCl shows Schottky defects and AgCl Frenkel defects. Their electrical conductivity is due to -
(a) Motion of ions and not the motion of electrons
(b) Motion of electrons and not the motion of ions
(c) Lower coordination number of NaCl
(d) Higher coordination number of AgCl
45. A piece of copper and another of Ge are cooled from room temp. to 80 K. The resistance of -
(a) Each of them increases
(b) Cu increases and that of Ge decrease
(c) Cu decrease and that of Ge increases
(d) Each of them decreases
46. If a crystal contains a total of N atoms, and n schottky defects are produced by removing n cations and r anions from the interior of the crystal then -
47. Choose the incorrect statement ?
(a) The crystal structure of rock salt in an fcc array of anions in which cations occupy all the octohedral voids
(b) The sphalerite crystal structure is an expanded fcc anion lattice with cations occupying one type of tetrahedral hole.
(c) In fluorite structure, cations occupy half the cubic holes of a primitive cubic array of anions.
(d) None of the above.
48. A solid has 3 types of atoms namely x, y and z, x forms a fcc lattice with y atoms occupying all the tetrahedral voids and z atoms occupying half the octohedral voids. The formula of the solid is -
(a) X2Y4Z (b) XY2Z2
(c) X4Y2Z (d) X4YZ2
49. KCl crystallises in the same type of lattice as does NaCl calculate the ratio of the side of the unit cell for KCl to that for NaCl
(a) 1.222 (b) 1.224
(c) 1.414 (d) 0.732
50. Some polar crystals produce small electric current on heating. This phenomenon is called-
(a) Piezo electricity (b) Pyroelectricity
(c) Ferroelectricity (d) Anti ferroelectricity
Hints and Solution
7. Solution : 8 corners with atom A are shared by 8 cubes. Thus no. of atoms of A in one unit cell = 1/8 x 8 = 1
6 Faces with atom B each of which is shared by two cubes. Hence no. of B atoms in one unit cell = 1/2 x 6=3
Formula of compound = AB3
8. Hint : In bcc lattic
9. Hint : (a) is incorrect because CsCl (8:8 coordination) on heating transform to NaCl structure (6 : 6 coordination) but reverse does not occur.
10. Solution : By the addition of Sr++, two Na+ions are removed and cationic vacancy is creacted.
No. of cationic vacancy = 2 x 10-3 mol % of NaCl
= 2 x 10-5 x 6.02 x 1023 per mol of NaCl
= 12.04 x 1018 per mol of NaCl
11. Solution :
For Na+Cl- product of charges = 1 x 1 = 1
For CaO product of charges = 2 x 2 = 4
While interionic distance remains almost same in both. Thus Lattice energy of CaO is four times of that of NaCl.
12. Hint : CsCl has a bcc structure.
15. Solution :
20. Solutions :
26. Hint/added information : Layered lattice structure is that seen in Graphite
38. Hint :
39. Solution :
41. Hint : Solve it with -43. Hint : Solve it with -