Iron has a body centred cubic unit cell with the cell dimension of 286.65 pm. Density of iron is 7.87 g cm^-3. The value of  Avogadro's number based on this data will be -

(Atomic mass of Fe = 56.0 u)

1. 6.04 x 10²³ mol^-1

2. 12.08 x 10²⁴ mol^-1

3. 6 x 10²² mol^-1

4. 6 x 10^-23 mol^-1

Iodine crystals are classified as-

1. Metallic solids.                                  

2. Ionic solids.

3. Molecular solids .                                 

4. Covalent solids.

If Xenon crystallizes in face center cubic lattice and the edge of the unit cell is 620 pm, then the radius of the Xenon atom is-

1. 219.20 pm                                   

2. 438.5 pm

3. 265.5 pm                                     

4. 536.94 pm

In a cubic unit cell, atom A is present at each corner, atom B at each face centre and atom C at the body centre. The simplest formula of the solid is :

1. ${\mathrm{AB}}_2\mathrm{C}$                                         

2. ${\mathrm{A}}_2\mathrm{BC}$

3. ${\mathrm{AB}}_3\mathrm{C}$                                         

4. ${\mathrm{ABC}}_3$

The unit cell dimensions of a cubic lattice (edges a, b, c and the angles between them, α, β, γ) are : 

1. a = b = c, $\mathrm{\alpha }= \mathrm{\beta }= \mathrm{\gamma }= 90°$

2. a = b $\ne$c, $\mathrm{\alpha }= \mathrm{\beta }= \mathrm{\gamma }= 90°$

3. a = b = c, $\mathrm{\alpha }= \mathrm{\gamma }= 90°,$ $\mathrm{\beta }\ne 90°$

4. a $\ne$b $\ne$c, $\mathrm{\alpha }= \mathrm{\beta }= 90°,$ $\mathrm{\gamma }\ne 90°$

1. a, b                                         

2. b, c

3. a, b, c                                     

4. a, c

The incorrect statement among the following is:

A metallic element exists as a cubic lattice. Each edge of the unit cell is 2.88 Å. The density of the metal is 7.20 g cm^–3.  The number of unit cells, that will be present in 100 gm of the metal is: 

1. 5.82 × 10²³

2. 16.33 × 10²³

3. 7.49 × 10²⁴

4. 6.9 × 10²⁴

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

1. NaCl

2. ZnS

3. CaF₂

4. Na₂O

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