An ionic compound has a unit cell consisting of A ions at the corners of a cube and B ions on the centers of the faces of the cube. The empirical formula for this compound would be : 

1. AB 

2. A₂B

3. AB₃

4. A₃B

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

The formula of nickel oxide with metal deficiency defect in its crystal is $N{i}_{0.98}O$. The crystal contains ${\mathrm{Ni}}^{2+}<mspace\; width="1em"></mspace>\mathrm{and}<mspace\; width="1em"></mspace>{\mathrm{Ni}}^{3+}$ 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

Select the correct option based on statements below:

Select the correct option based on statements below:

Select the correct option based on statements below:

An element occurring in the bcc structure has $12.08\times {10}^{23}$ unit cells. The total number of atoms of the element in these cells will be:

1. $24.16\times {10}^{23}$

2. $36.18\times {10}^{23}$

3. $6.04\times {10}^{23}$

4. $12.08\times {10}^{23}$

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

1. ZnS               

2. AgBr             

3. NaCl                 

4. AgCl

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$\times 6.02\times {10}^{23}$

If an element (at. Wt. = 50) crystallises in fcc lattice, with a = 0.50 nm, then the density of unit cell if it contains 0.25 % Schottky defect is -

(Use $N_A=6\times {10}^{23}$) 

1. 2.0 g/cc

2. 2.66 g/cc

3. 3.06 g/cc

4. None of the above.