If NaCl is doped with 10^-4 mol % of ${\mathrm{SrCl}}_2$, the concentration of cation vacancies will be -
(N_A = 6.023 x 10²³ mol^-1)                                                                             
1. 6.023 x 10¹⁵ mol^-1             
2. 6.023 x 10¹⁶ mol^-1
3. 6.023 x 10¹⁷ mol^-1             
4. 6.023 x 10¹⁴ mol^-1                                     

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

(A) 500 pm
(B) 693 pm
(C) 600 pm
(D) 566 pm

Total volume of atoms present in a face centred cubic unit cell of a metal is ( r is atomic radius):

(1) 20/3 $\pi$r³

(2)  24/3 $\pi$r³

(3)  12/3 $\pi$r³

(4)  16/3 $\pi$r³

A solid has a bcc structure. If the distance of closest approach between the two atoms is 1.73Å . The edge length of the cell is:

(a) 200pm

(b) $\raisebox{1ex}{$\sqrt{3}$}\!\left/ \!\raisebox{-1ex}{$\sqrt{2}$}\right.$ pm

(c) 142.2 pm

(d) $\sqrt{2}$pm

Which is covalent solid?

(1) Fe₂O₃

(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. then the general formula of the compound is-

(1) CA

(2) A₂

(3) C₂A₃

(4) C₃A₂

Graphite in an example of-

(1) Ionic solid

(2) Covalent solid

(3) Vander waal's crystal

(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,

(A) a,b

(B) b,c

(C) a,b,c

(D) a,c

Which arrangement of electrons leads to anti-ferromagnetism?
(1)  ↑↑↑↑
(2)  ↑↓↑↓
(3) Both (a) and (b)
(4) None of these

Among the following types of voids. which one is the largest void:-

(A) Triangular system
(B) Tetragonal system
(C) Monoclinic system
(D) Octahedral