The radius of Ag⁺ ion is 126 pm and that I^- ion is 216 pm. The coordination number of Ag⁺ ion is

1. 2

2. 4

3. 6

4. 8

Schottky defect occurs mainly in electrovalent compounds where :

1. Positive ions have large sizes.

2. Negative ions have small sizes.

3. Positive and negative ions are of similar size.

4. Positive ions are big and negative ions are small.

Analysis shows that an oxide ore of  nickel has formula  Ni_0.98O_1.00. The percentage of nickel as Ni³⁺ ions is nearly

1. 2

2. 96

3. 4

4. 98

The appearance of color in solid alkali metal halides is generally due to:-

1. Frenkel Defect

2. Interstitial Defect

3. F-Centres

4. Schottky Defect

Ice crystallizes in a hexagonal lattice having the volume of the unit cell as $132\times {10}^{-24}$ $c{m}^3$. If the density is 0.92 g/cm³ at a given temperature, then the number of H₂O molecules per unit cell is : 

1. 1

2. 2

3. 3

4. 4

AB crystallizes in a body-centred cubic lattice with edge length a equal to 387 pm. The distance between two oppositely charged ions in the lattice will be : 

1. 250 pm

2. 200 pm

3. 300 pm

4. 335 pm

In a face centred cubic lattice, atom A occupies the corner positions and atom B occupies the face
centre positions. If one atom of B is missing from one of the face centred points, the formula of the compound is

1.AB₂

2.A₂B₃

3.A₂B₅

4.A₂B

Percentage of free space in cubic close packed structure and in body centered packed structure are respectively:

1. 48% and 26%

2. 30% and 26%

3. 26% and 32%

4. 32% and 48%

Packing fraction of simple cubic crystal lattice is 

1. 38%

2. 74%

3. 68%

4. 52.4%

In which of the following crystals are alternate tetrahedral voids occupied:

1. NaCl

2. ZnS

3. CaF₂

4. Na₂O