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1.

The density of KCl is 1.9893 g cm^-3 and the length of a side unit cell is 6.29082 Å as determined by X-ray diffraction. The value of Avogadro’s number calculated from this data is:-
1. 6.017 x 10²³
2. 6.023 x 10²²
3. 7.03 x 10²³
4. 6.01 x 10¹⁹

2.

8 : 8 co-ordination of CsCl is found to change into 6 : 6 co-ordination on:
1. Applying pressure.
2. Increasing temperature.
3. Both 1 and 2.
4. None of these.

3.

An element X (At. Wt = 80 g/mol) having fcc structure, calculate no. of unit cells in 8 gm of X:
1. 0.4 X ${\mathrm{N}}_{\mathrm{A}}$
2. 0.1 X ${\mathrm{N}}_{\mathrm{A}}$
3. 4 X ${\mathrm{N}}_{\mathrm{A}}$
4. None of these

4.

In the spinel structure, oxide ions are cubical-closest packed whereas 1/8th of tetrahedral voids are occupied by ${\mathrm{A}}^{2+}$ cation, and 1/2 of octahedral voids are occupied by ${\mathrm{B}}^{3+}$ cations. The general formula of the compound having a spinel structure is:
1. ${\mathrm{A}}_2{\mathrm{B}}_2{\mathrm{O}}_4$
2. ${\mathrm{AB}}_2{\mathrm{O}}_4$
3. ${\mathrm{A}}_2{\mathrm{B}}_4{\mathrm{O}}_2$
4. ${\mathrm{A}}_4{\mathrm{B}}_2{\mathrm{O}}_2$

5.

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

6.

Dopping of AgCl crystals with ${\mathrm{CdCl}}_2$ results in:
1. Schottky defect
2. Frenkel defect
3. Substitutional cation vacancy
4. Formation of F-centres

7.

KCl crystallizes in the same type of lattice as does NaCl. Given that ${{\mathrm{r}}_{\mathrm{Na}}}^{+}/{{\mathrm{r}}_{\mathrm{cl}}}^{-}$ = 0.50 and ${{\mathrm{r}}_{\mathrm{Na}}}^{+}/{{\mathrm{r}}_{\mathrm{k}}}^{+}$ = 0.70, calculate the ratio of the side of the unit cell for KCI to that for Nacl:
1. 1.143
2. 1.224
3. 1.414
4. 0.875

8.

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

9.

The composition of a sample of Wustite is ${\mathrm{Fe}}_{0.93}\mathrm{O}$. What is the percentage of iron present as ${\mathrm{Fe}}^{3+}$ in total iron ?
1. 15.05 %
2. 25 %
3. 35 %
4. 45 % 

10.

Sodium (Na = 23) crystallises in bcc arrangement with the interfacial separation between the atoms at the edge 53.6 pm. The density of sodium crystal is;
(1) 2.07 g/cc
(2) 2.46 g/cc
(3) 1.19 g/cc
(4) none of these 

11.

A body centered cubic lattice is made up of hollow spheres of B. Spheres of solid A are present in hollow spheres of B. Radius of A is half of radius of B. What is the ratio of total volume of spheres of B unoccupied by A in a unit cell and volume of unit cell?
(1) $\frac{7\sqrt{3\mathrm{\pi }}}{64}$
(2) $\frac{7\sqrt{3}}{128}$
(3) $\frac{7.\mathrm{\pi }}{24}$
(4) None of these

12.

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.

13. Assertion(A): In any ionic solid [MX] with Schottky defects, the number of positive and negative ions missing is the same. 
Reason(R): Equal number of cation and anion vacancies are present. 
1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true and R is false.
4. A is false and R is true.
 

14. Assertion(A): Amorphous solids are isotropic. 
Reason(R): Amorphous solids lack a regular three-dimensional arrangement of atoms. 
1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true and R is false.
4. A is false and R is true.

15. Assertion(A): Diamond is a covalent solid.
Reason(R): The Co-ordination number of each carbon atom in diamond is 4.  
1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true and R is false.
4. A is false and R is true.

16. Assertion(A): In NaCl structure, Na⁺ ions occupy octahedral holes, and Cl^- ions occupy ccp. 
Reason(R): The distance of the nearest neighbors in NaCl structure is \(a/2 \) where \(a \) is the edge length of the cube.
1. Both A and R are true and R is the correct explanation of A.
2.  Both A and R are true but R is not the correct explanation of A.
3. A is true and R is false.
4. A is false and R is true.

17. Assertion(A): For fluorite structure, the F^- ions occupy tetrahedral void and Ca²⁺ions in ccp.
Reason(R): The radius ratio of fluorite structure is 0.414.
1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true and R is false.
4. A is false and R is true. 

18. Assertion(A): In the body-centered cubic type structure of CsCl the arrangement of Cs⁺ is present in the central octahedral void. 
Reason(R): In CsCl, the Cs⁺  ion at body centered position and Cl^- at corners.
1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true and R is false.
4. A is false and R is true.

19. Assertion(A): Electrical conductivity of semiconductors increases with increasing temperature.
Reason(R): With the increase in temperature, the number of electrons from the valence bond can jump to the conduction band in semiconductors.
1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true and R is false.
4. A is false and R is true.

20. Assertion(A): FeO is non-stoichiometric with Fe_0.95O.
Reason(R): Some Fe²⁺ ions are replaced by Fe³⁺ as 3Fe²⁺ = 2Fe³⁺ to maintain electrical neutrality. 
1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true and R is false.
4. A is false and R is true.

21. Assertion(A): The number of tetrahedral voids is double the number of an octahedral void.
Reason(R): The size of the tetrahedral void is half of that of the octahedral void.
1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true and R is false.
4. A is false and R is true.

22. Assertion(A): Due to Frenkel defect there is no effect on density of solid.
Reason(R): Ions shift from lattice sites to interstitial sites in Frenkel defect.
1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true and R is false.
4. A is false and R is true.

23. Assertion(A): Ferrimagnetism is observed when the magnetic moments of the domains in the substance are aligned in parallel and anti-parallel directions in unequal numbers
Reason(R): Substances also lose ferrimagnetism on heating and become paramagnetic.
1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true and R is false.
4. A is false and R is true.

24. Assertion(A): Iconic crystals have the highest melting point.
Reason(R): Covalent bonds are stronger than ionic bonds.
1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true and R is false.
4. A is false and R is true.

25.

ln a solid 'AB' having the NaCl structure, 'A' atoms occupy the corners of the cubic unit cell. lf all the face centred atoms along one of the axis are removed, then the resultant stoichiometry of the solid is :
(1) AB${}_2$
(2) A${}_2$B
(3) $A_4{B}_5$
(4) $A_3{B}_4$

26.

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 $g/c{m}^3$

27.

An element has a body-centred cubic (bcc) structure with a cell edge of 288 pm. The density of the element is 7.2 g/cm³. The number of atoms present in 208 g of the element are
1. 14.16×10²¹ atoms
2. 24.16×10²¹ atoms
3. 14.16×10²³ atoms
4. 24.16×10²³ atoms

28.

How many unit cells are present in a cube shaped ideal crystal of NaCl of mass 1.00g?
[ Atomic masses Na=23, Cl = 35.5]
1. 2.57 x 10²¹
2. 5.14 x 10²¹
3. 1.28 x 10²¹
4. 1.71 x 10²¹

29. The number of \(Na^+\) ions and \(Cl^-\) ions (part or full) required to form one unit cell of \(NaCl\) , respectively, are 
1. 4 and 4 
2. 13 and 14 
3. 14 and 13 
4.  6 and 6

30. Case study : 
A compound is made up of A, B and C atoms. In a cubic unit cell, A atoms are present on alternate corners, B atoms are present on alternate faces and C atoms are present on alternate edges. 
A rectangular plane is placed in the unit cell and all the atoms are removed which are touching the rectangular plane. After the removal of atoms, the simplest formula of the compound cannot be 
1. AB₂C₂
2. AB₂ 
3. AC₂ 
4. ABC₂

31.

An ionic compound AB has fluorite type structures. If the radius  ${\mathrm{B}}^{-}$ is 200 pm, then the ideal radius of ${\mathrm{A}}^{+}$ would be :
1. 82.8 pm
2. 146.4 pm
3. 40 om
4. 45 pm

32. The non-stoichiometric compound Cu₁.₈S is prepared by the incorporation of Cu²⁺ ion in the lattice of Cuprous sulphide. The percentage of Cu²⁺ ions in the total content of the compound is:
1.  88.88
2.  11.11
3.  89.8
4.  99.8