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An example of fluorite structure is

a. NaF b. SrF 2 c. AlCl 3 d.SiF4 Ans.b Explanation : SrF 2 has fluorite type structure. (8)

A metal crystallizes in a face centred structure. If the edge length of its unit cell is ‘a’ the closest approach between two atoms in metallic crystal will be

a. 2√2a b. √2a c.a / √2 d. 2a Ans. c (5)

A solid having density of

9 x 103 kg m-3 forms face centred cubic crystals of edge length 200 √2 pm. What is the molar mass of of the solid a. 0.0432 kg mol -1 b. 0.0305 kg mol -1 c. 0.4320 kg mol-1 d. 0. 0216 …

Body centered cubic lattice has a coordination number of

a. 4 b. 8 c. 12 d. 6 Ans. b Explanation : Body centered cubic lattice has a coordination number 8. (11)

A solid has a structure in which ‘W’ atoms are located at the corners of a cubic lattice ‘O’ atoms at the centre of edges and Na atoms at the centre of the cube. The formula for the compound is

a. NaWO2 b. NaWO3 c. NaWO3 d. NaWO4 Ans. b (7)

In the cubic close packing the unit cell has…….

a. 4 tetrahedral voids each of which is shared by four adjacent unit cells. b. 4 tetrahedral voids within the unit cell c. 8 tetrahedral voids each of which is shared by four adjacent unit cells d. 8 tetrahedral voids …

At

100° C , copper (Cu) has fcc unit cell structure with cell edge length of x Å. What is the approximate density of Cu ( in g cm-3 ) at this temperature ? a. 205/ x3 b. 105/ x3 c. …

In metallic solids the number of atoms for the face centered and the body centered cubic unit cells are respectively

a. 2, 4 b. 2, 2 c. 4, 2 d. 4, 4 Ans. c (3)

The number of atoms in 100 g of an fcc crystal with density d = 10 g/cm ^3 and cell edge equal to 100 pm is equal to

a. 4 x 10 25 b. 3x 1025 c. 2x 1025 d. 1x 1025 Ans. a (6)

Bragg’s law is given by the equation

a. nλ = 2 θ sin θ b. nλ = 2d sin θ c. 2nλ = dsin θ d. n (θ /2) = d/2 θ Ans. b (12)

CsBr crystallises in a body centred cubic lattice. The unit cell length is 436.6 pm. Given that the atomic mass of Cs = 133 and that of Br = 80 amu and Avogadro number being =

6.023 x 1023 mol -1 CsBr. the density of CsBr is a. 8.25 g/ cm3 b. 4.25 g/cm3 c. 42.5g /cm3 d. 0.425g / cm3 Ans. b (41)

Total volume of atoms present in face- centred cubic unit cell of a metal is (r is atomic radius)

a. 20/3 (πr 3 ) b. 24/ 3 (πr 3 ) c. 12/3 (πr 3 ) d. 16/3 (πr 3 ) Ans. d (11)

1. The fraction of total volume occupied by the atoms present in a simple cube is

a. π/6 b. π 3√2 c. π /4√2 d. π/ 4 Ans. a (5)

An ionic compound is formed between a metal M and a non metal Y. If M occupies half the octahedral voids in the cubic close packed arrangement formed by Y, the chemical formula of the ionic compound is

a. My b. My 2 c. M 2 Y d. MY 3 Ans. b (6)

In a cubic close packed structure, fractional contributions of an atoms at the corner and at the face in the unit cell are respectively

a. 1/8 and 1/2 b. 1/2 and 1/4 c. 1/4 and 1/2 d. 1/4 and 1/8 Ans. a (10)

Consider the bcc unit cells of the solids 1 and 2 with the position of atoms as shown below. The radius of atom B is twice that of atom A. The unit cell edge length is 50% more in solid 2 than in 1. What is the approximate packing efficiency in solid 2

a. 65% b. 45% c. 90% d. 75% Ans. c (8)

In NaCl unit cell all the ions lying along the axis as shown in the figure are removed. Then the number of

Na+ and Cl – ions remaining in the unit cell are a. 4 and 4 b. 3 and 3 c. 1 and 1 d. 4 and 3 Ans. b (16)

The packing efficiency of the two dimensional square unit cell shown below is

a. 39.27 % b. 68.02% c. 74.05 % d. 78. 54 % Ans. d (5)

A compound is formed by cation C and antion A . The anions form hexagonal close packed (hcp) lattice and the cations occupy 75% of octahedral voids. The formula of the compounds is

a. C 4 A 3 b. C2 A3 c. C 3 A 2 d. C 3 A 4 Ans. d (5)

The radius of the largest sphere which fits properly at the centre of the edge of body centred cubic unit cell is : (Edge length is represented by ‘a’)

a. 0.047 a b. 0.027 a c. 0.134 a d. 0.067 a Ans. d (11)

Iron exhibits bcc structure at room temperature. Above

900º C It transforms to fcc structure. the ratio of density of iron at room temperature to that at 900 º C (assuming molar mass and atomic radii of iron remains constant with temperature ) is a. √3 /√2 b. …

Total no. of voids in o.5 mole of compound forming hexagonal closed packed structure are

a. 6. 022 x 1023 b. 3. 011 x 1023 c. 9. 033 x 1023 d. 4. 516 x 1023 Ans. c (5)

Which of the following statements is not correct

a. The number of carbon atoms in an unit cell of diamond is 4 b. The number of bravais latties in which a crystal can be categorized is 14 c. The fraction of the total volume occupied by the atoms …

Given that the radius of

Na+ ion is 0.95 Å and that of Cl– ion is 1.81 Å hence in the close packed lattice of Cl – ions Na+ ions prefer to occupy a. Tetrahedral site b. Octahedral site c. Cubic site d. Trigonal site …

The edge length of face centred unit cubic cell is 508 pm. If the radius of the cation is 110 pm, the radius of the anion is

a. 285 pm b. 398 pm c. 144 pm d. 618 pm Ans. c (10)

In face centred cubic unit cell, what is the volume occupied

a. 4/3 π r 3 b. 8/3 π r 3 c. 16/3 π r 3 d. 64π r 3 / 3√3 Ans. c (8)

The contribution of particle at the edge centre of a particular unit cell is

a. 1/2 b. 1/4 c. 1 d. 1/8 Ans. b (31)

CsCl crystallizes in body centred structure. The length of the side of its unit cell is 351 pm. Atomic radius of the lithium will be

a. r cs + + r cl- = 3a b. r cs + + r cl- = 3a/ 2 c. r cs + + r cl- = √3/2 a d. r cs + + r cl- …

Lithium forms body centred cubic structure. The length of the side of its unit cell is 351 pm. Atomic radius of the lithium will be

a. 75 pm b. 300 pm c. 240 pm d. 152 Ans. d (4)

A metal crystallizes with a face – centered cubic lattice. The edge of the unit cell is 408 pm. The diameter of the metal atom is

a. 288 pm b. 408 pm c. 144 pm d. 204 pm Ans. a (15)

AB crystallizers in a body centred cubic lattice with edge length ‘a’ equal to 387 pm. The distance between two oppositively charged ions in the lattice is

a. 300 pm b. 335 pm c. 250 pm d. 204 pm Ans. b (10)

Copper crystallises in fcc with a unit cell length of 361 pm. What is the radius of copper atom

a. 108 pm b. 127 pm c. 157 pm d. 181 pm Ans. b (9)

Sodium metal crystallizes in a body centred cubic lattice with a until cell edge of 4.24 Å . The radius of sodium atom is approximately

a. 1. 86 Å b. 3.22 Å c. 5.72 Å d. 0.93 Å Ans. a (3)

CsBr crystal has bcc structure. It has an edge lenght of 4. 3 Å The shortest interionic distance between

Cs + and Br – ions is a. 1. 86 Å b. 3.72 Å c. 4. 3 Å d. 7. 44 Å Ans. b (7)

The number of octahedral void (s) per atom present in a cubic close packed structure is

a. 1 b. 3 c. 2 d. 4 Ans. a Explanation : Number of octahedral voids in ccp, is equal to effective number of atoms. In ccp, effective number of atoms are 4 so, 4 octahedra voids. So, 1 octahedral …