Solid State

The appearance of colour in solid alkali metal halides is generally due to

1. interstitial positions
2. F-centres
3. Schottky defect
4. Frenkel defect

CsBr crystallises in a body centered 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 6.02 1023 mol-1, the density of CsBr is

1. 4.25 g/cm3
2. 42.5 g/cm3
3. 0.425 g/cm3
4. 8.25 g/cm3

Copper has face centered cubic (fcc) lattice with interatomic spacing equal to 2.54 A. The value of lattice constant for this lattice is

1. 2.54 A
2. 3.59 A
3. 1.27 A
4. 5.08 A

In a face-centered cubic lattice, a unit cell is shared equally by how many unit cells?

1. 2
2. 4
3. 6
4. 8

A compound formed by elements X and Y crystallizes in a cubic structure in which the X atoms are at the corners of a cube and the Y atoms are at the face-centers. The formula of the compound is :-

1. XY3
2. X3Y
3. XY
4. XY2

The pyknometric density of sodium chloride crystal is 2.165 103 kg m-3 while its X-ray density is 2.178 103 kg m-3. The fraction of unoccupied sites in sodium chloride crystal is

1. 5.96
2. 5.96 10-2
3. 5.96 10-1
4. 5.96 10-3

Number of atoms per unit cell in B.C.C. is

1. 9
2. 4
3. 2
4. 1

When Zn converts from melted state to its solid state, it has hcp structure, then find the number of nearest atoms.

1. 6
2. 8
3. 12
4. 4

The cations and anions are arranged in alternate form in

1. metallic crystal
2. ionic crystal
3. covalent crystal
4. semi-conductor crystal

Cations and anions combine in a crystal to form the following type of compound

1. ionic
2. metallic
3. covalent
4. dipole-dipole