The incorrect statement among the following is -

1.	Density decreases in case of crystals with Schottky's defect.
2.	NaCl(s) is insulator, silicon is semiconductor, silver is conductor, quartz is piezo electric crystal.
3.	Frenkel defect is favoured in those ionic compounds in which sizes of cations and anions have large difference.
4.	\(Fe_{0.98}O\) has non stoichiometric metal excess defect.

Iron exhibits bcc structure at room temperature. Above 900 °C, it transforms to fcc structure. The ratio of density of iron at room temperature to that at 900 °C is:

(Molar mass and atomic radii of iron remain constant with temperature) 

1. $\frac{\sqrt{3}}{\sqrt{2}}$

2. $\frac{4\sqrt{3}}{3\sqrt{2}}$

3. $\frac{3\sqrt{3}}{4\sqrt{2}}$

4. $\frac{1}{2}$

The correct statement regarding defects in a crystalline solid is:

The vacant space in the BCC lattice cell is: 

1. 26%

2. 48%

3. 23%

4. 32%

A given metal crystallizes out with a cubic structure having an edge length of 361 pm. If there are four metal atoms in one unit cell, the radius of one atom is:

1. 40 pm
2. 127 pm
3. 80 pm
4. 108 pm

If a is the length of the side of a cube, the distance between the body-centered atom and one corner atom in the cube will be:

1. $\frac{2}{\sqrt{3}}a$

2. $\frac{4}{\sqrt{3}}a$

3. $\frac{\sqrt{3}}{4}a$

4. $\frac{\sqrt{3}}{2}a$

The number of carbon atoms per unit cell of a diamond is:

1. 8

2. 6

3. 1

4. 4

A metal crystallizes with a fcc lattice. The edge of the unit cell is 408 pm. The diameter of the metal atom is: 

1. 288 pm

2. 408 pm

3. 144 pm

4. 204 pm