An element crystallizes in a structure having FCC unit cell of an edge length 200 pm. If 200 g of this element contains 24 x 10²³ atoms, the density of the element is - 

1. 50.3 g/cc 

2. 63.4 g/cc

3. 41.6 g/cc 

4. 34.8 g/cc

If NaCl is doped with ${10}^{-5}$ mol% of $SrC{l}_2$, the number of cation vacancies will be - 

1. $6.02\times {10}^{16}$                 

2. $6.02\times {10}^{18}$

3. $6.02\times {10}^{20}$                 

 4. 2$\times 6.02\times {10}^{23}$

A compound that shows Schottky as well as Frenkel defect among the following is -

1. ZnS               

2. AgBr             

3. NaCl                 

4. AgCl

The formula of nickel oxide with metal deficiency defect in its crystal is $N{i}_{0.98}O$. The crystal contains ${\mathrm{Ni}}^{2+} \mathrm{and} {\mathrm{Ni}}^{3+}$ ions. The fraction of nickel existing as $N{i}^{2+}$ ions in the crystal is-

1. 0.96

2. 0.04

3. 0.50

4. 0.31

A compound is formed by cation C and anion A. The anions form hexagonal close packed (hcp) lattice and the cations occupy 75 % of octahedral voids. The formula of the compound is:

1. ${\mathrm{C}}_3{\mathrm{A}}_4$

2. ${\mathrm{C}}_2{\mathrm{A}}_3$

3. ${\mathrm{C}}_3{\mathrm{A}}_2$

4. ${\mathrm{C}}_4{\mathrm{A}}_3$

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

1. F-centres.

2. Schottky defect.

3. Frenkel defect.

4. Interstitial positions.

CsBr crystallises in a body-centered cubic lattice. The unit cell length is 436.6 pm. Given that the atomic mass of Cs = 133 amu and that of Br = 80 amu and the Avogadro number being 6.02×10²³ mol^-1, the density of CsBr is:

1. 42.5 $g/c{m}^3$

2. 0.425 $g/c{m}^3$

3. 8.25 $g/c{m}^3$

4. 4.25 $g/c{m}^3$

The fraction of total volume occupied by the atoms present in a simple cube is:

1. $\frac{\mathrm{\pi }}{6}$

2. $\frac{\mathrm{\pi }}{3\sqrt{2}}$

3. $\frac{\mathrm{\pi }}{4\sqrt{2}}$

4. $\frac{\mathrm{\pi }}{4}$

Silicon gives p-type of semiconductor on doping with:

1. Germanium.

2. Arsenic.

3. Selenium.

4. Boron.