The edge length of cube is 400pm. Its body diagonal would be-

1. 500 pm

2. 693 pm

3. 600 pm

4. 566 pm

Lithium borohydride (LiBH₄), crystallizes in an orthorhombic system with 4 molecules per unit cell. The unit cell dimensions are:- a = 6.81 Å , b = 4.43 Å, c = 7.17 Å. If the molar mass of LiBH₄ is 21.76 g mol^-1, then the density of the crystal is:-

1. 0.67 g cm^-3

2. 0.58 g cm^-3

3. 1.23 g cm^-3

4. None of the above.

The arrangement of X^- ions around A⁺ ion in solid AX is given in the figure (not drawn to scale).
If the radius of X^-  is 250 pm, the radius of A⁺ is: 

1. 104 pm

2. 125 pm

3. 183 pm

4. 57 pm

Which is covalent solid?

1. Silicate

2. Diamond

3. Graphite 

4. All of these

The anions (A) form hexagonal closest packing and atoms (C) occupy only 2/3 of octahedral voids in it. The general formula of the compound is-
1. CA
2. CA₂
3. C₂A₃
4. C₃A₂

Graphite in an example of-

1. Ionic solid

2. Covalent solid

3. Molecular Solids

4. Metallic crystal

Select the correct statement (s)-

(a) The C.N. of cation occupying a tetrahedral hole is 4.

(b) The C.N. of cation occupying a octahedral hole is 6.

(c) In schottky defects, density of the lattice decreases,

1. a,b

2. b,c

3. a,b,c

4. a,c

The arrangement ABC ABC.. is referred to as.

1. octahedral close packing

2. hexagonal clase packing

3. tetrahedral close packing

4. cubic close packing

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

The most efficient packing of similar spheres is obtained in 

1. The simple cubic system and the body centered cubic system

2. The simple cubic system and the hexagonal close packed system

3. The face centered cubic system and the hexagonal close packed system

4. The body centered cubic system and the face centered cubic system