How many unit cells are present in a cube shaped ideal crystal of NaCl of mass 1.00g?

[ Atomic masses Na=23, Cl = 35.5]

1. 2.57 x 10²¹

2. 5.14 x 10²¹

3. 1.28 x 10²¹

4. 1.71 x 10²¹

The ratio of cations to anion in a closed pack tetrahedral is:

1. 0.714

2. 0.225

3. 0.02

4. none of these

In a compound, atoms of element Y form ccp lattice, and those of element X occupy 2/3^rd of tetrahedral voids. The formula of the compound will be :-
1. X₃Y₄
2. X₄Y₃ 
3. X₂Y₃
4. X₂Y

A spinel is an important class of oxides consisting of two types of metal ions with the oxide ions arranged in ccp layers. The normal spinel has 1/8^th of the tetrahedral void occupied  by one type of metal and one half of the octahedral voids occupied by another type of metal ions. Such a spinel is formed by Zn²⁺, Al³⁺ and O^2- with Zn²⁺ in tetrahedral void. Give the simplest formula of the spinel.

1. ZnAl₂O₄

2. ZnAl₂O₃

3. ZnAlO

4. None of these

Close packing is maximum in the crystal lattice of:

1. simple cubic

2. face centred

3. body centred

4. none of these

Frenkel defect is noticed in:

1. AgBr

2. ZnS

3. Agl

4. All of the above

The density of KCl is 1.9893 g cm^-3 and the length of a side unit cell is 6.29082 Å as determined by X-ray diffraction. The value of Avogadro’s number calculated from this data is:-

1. 6.017 x 10²³

2. 6.023 x 10²²

3. 7.03 x 10²³

4. 6.01 x 10¹⁹

How many octahedral and tetrahedral holes are present per unit cell in a face centred cubic arrangement of atoms?

1. 8,4

2. 1,2

3. 4,8

4. 2 ,1

TiO₂ is a well-known example of:

1. Triclinic system.

2. Tetragonal system.

3. Monoclinic system.

4. None of the above.

For a solid with the following structure, the co-ordination number of the point B is:

1. 3

2. 4

3. 5

4. 6