Please be patient as the PDF generation may take upto a minute.

The density of solid argon (Ar=40 g/mol) is 1.68 g/mL at 40 K. If the argon atom is assumed to be a sphere of radius 1.50$\times {10}^{-8} cm$, what % of solid Ar is having apparently empty space?
(Use N_A=6$\times {10}^{23}$)
(1) 35.64
(2) 64.36
(3) 74%
(4) None of these

First three nearest neighbour distances for primitive cubic lattice are respectively (edge length of unit cell = a):
(1) a, $\sqrt{2}a, \sqrt{3}a$
(2) $\sqrt{3}a, \sqrt{2}a, a$
(3) $a, \sqrt{2}a, 2a$
(4) $a, \sqrt{3}a, 2a$

First three nearest neighbour distances for body centered cubic lattice are respectively:
(1) $\sqrt{2}a, a, \sqrt{3}a$
(2) $\frac{a}{\sqrt{2}}, a, \sqrt{3}a$
(3) $\frac{\sqrt{3}a}{2}, a, \sqrt{2}a$
(4) $\frac{\sqrt{3}a}{2}, a, \sqrt{3}a$

Given: The unit cell structure of compound is shown below.

The formula of compound is:
(1) $A_8{B}_{12}{C}_5$
(2) $A{B}_2{C}_3$
(3) $A_2{B}_2{C}_5$
(4) $AB{C}_5$

The density of a pure substance 'A' whose atoms are in cubic close pack arrangement is 1 g/cc. If all the tetrahedral voids are occupied by 'B' atom, what is the density of resulting solid in g/cc. [Atomic mass (A) = 30 g/mol and atomic mass (B) = 50 g/mol]
(1) 3.33
(2) 4.33
(3) 2.33
(4) 5.33

In a planar tetra-atomic molecule, $X{Y}_3$, X is at the centroid of the equilateral triangle formed by the atoms, Y. If the X-Y bond distance is 1 $\stackrel{0}{A}$, what is the distance between the centres of any two Y atoms?
(1) $1/\sqrt{3} \stackrel{0}{A}$
(2) $\sqrt{2}\stackrel{0}{A}$
(3) $\sqrt{3} \stackrel{0}{A}$
(4) $1/\sqrt{2} \stackrel{0}{A}$

How many unit cells are present in 5.0 gm of crystal AB (formula mass of AB=40) having rock salt type structure? (N_A=Avogadro's no.)
(1) N_A
(2) $\frac{N_A}{10}$
(3) 4 N_A
(4) None of these

The density of CaF₂ (fluorine structure) is 3.18 g/cm³. The length of the side of the unit cell is:
(1) 253 pm
(2) 344 pm
(3) 546 pm
(4) 273 pm

A crystal of lead (II) sulphide has NaCl structure. In this crystal the shortest distance between a Pb²⁺ ion and S^2- ion is 297 pm. What is the volume of unit cell in lead sulphide?
(1) 209.6 $\times {10}^{-24} c{m}^3$
(2) 2.07.8 $\times {10}^{-23} c{m}^3$
(3) 22.3 $\times {10}^{-23} c{m}^3$
(4) 2.09.8 $\times {10}^{-23} c{m}^3$

CdO has NaCl structures with density 8.27 g/cc. If the ionic radius of O^2- is 1.24 $\stackrel{0}{A}$, determine ionic radius of Cd²⁺ :
(1) 1.5 $\stackrel{0}{A}$
(2) 1.1 $\stackrel{0}{A}$
(3) 1.9 $\stackrel{0}{A}$
(4) 1.5 $\stackrel{0}{A}$

KCl crystallizes in the same type of lattice as does NaCl. Given that $r_{N{A}^{+}}/r_{C{l}^{-}}=0.50$ and ${\mathrm{r}}_{{\mathrm{Na}}^{+}}/{\mathrm{r}}_{{\mathrm{K}}^{+}}$=0.70, calculate the ratio of the side of the unit cell for KCl to that for NaCl:
(1) 1.143
(2) 1.224
(3) 1.414
(4) 0.875

Ferrous oxide has a cubic structure and edge length of the unit cell is 5.0 $\stackrel{0}{A}$. Assuming the density of ferrous oxide to be 3.84 $g/m^3$, the no. of $F{e}^{2+} and O^{2-}$ ions present in each unit cell be : $(\mathrm{Use} {\mathrm{N}}_{\mathrm{A}}=6\times {10}^{23}):$
(1) $4 F{e}^{2+} and 4O^{2-}$
(2) $2 F{e}^{2+} and 2O^{2-}$
(3) $1 F{e}^{2+} and 1 O^{2-}$
(4) $3 F{e}^{2+} and 4O^{2-}$

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.

What is two dimensional co-ordination number of an atom in sqaure closed packed layer?
(1) 6
(2) 4
(3) 8
(4) 12

In a hexagonal close packed (hcp) structure of spheres, the fraction of the volume occupied by the sphere is A. In a cubic close packed structure the fraction is B. The relation for A and B is:
(1) A = B
(2) A < B
(3) A > B
(4) A is equal to the fraction in a simple cubic lattice

In which of the following pairs of structures, tetrahedral as well as octahedral holes are found?
(1) bcc and fcc
(2) hcp and simple cubic
(3) hcp and ccp
(4) bcc and hcp

The unit cell of diamond is made up of:
(1) 6 carbon atoms, 4 atoms consitute ccp and two atoms occupy half of octahedral voids
(2) 8 carbon atoms, 4 atoms constitute ccp and 4 atoms occupy all the octahedral voids
(3) 8 carbon atoms, 4 atoms form fcc lattice and 4 atoms occupy half of the tetrahedral void alternately
(4) 12 carbon atoms, 4 atoms form fcc lattice and 8 atoms occupy all the tetrahedral hole

Which is correct statement?
(1) When temperature increases then number of defects decreases.
(2) Schottky defect occurs when radius of cation is smaller
(3) Frenkel defect occurs when radius of cation is smaller
(4) None of these

Which of the following defects does KBr show?
(1) Frenkel
(2) Schottky
(3) Metal excess
(4) Metal deficiency

Dopping of AgCl crystals with CdCl₂ results in:
(1) Schottky defect
(2) Frenkel defect
(3) Substitutional cation vacancy
(4) Formation of F-centres