Solid State Sr Co Ipl

SOLID STATE

Single answer type questions:

1. An alloy of two metals Q and R has a cubic structure. The unit cell may be described as cubic close packed with respect to metal atoms Q. The R atoms are in the body centres of alternate minicubes made by partitioning the main cube into 8 equal parts as shown in the diagram.

a

a

a On the basis of description given above, identify the incorrect conclusion

(A) The number of nearest neighbors of R is 4 (B) The radius of R atom is less than that of Q atoms

(C) The angle made by the line connecting any R atom with two of its nearest neighbors (Q atoms) is 109°28. (D) The number of nearest neighbors of Q is 8.

2. The non-stoichiometric compound

Fe

_0.94O is formed when

x

%

of

Fe

2 ions are replaced by

Fe

3 ions then

x

is

(A) 6 (B) 12

(C) 15 (D) 18

3. A cation is in the centre touches three anions. Assume that the anions also touch each other. The limiting

radius ratio,

r

r

  is

A) 0.1547 B) 0.4141 C) 0.7322 D) 0.2252

4. Total volume of atoms present in a face-centered cubic unit cell is (where r is atomic radius)

(A)

12

r

3

3



(B) 3

16

r

3



(C)

20

r

3

3



(D) 3

24

r

3



5. When NaCl is doped with

1 10



4mole of

SrCl

₂, the no. of cation vacancies are

A)

6.023 10



18 B)

6.023 10



19 C)

6.023 10



20 D)

3.011 10



20

6.

The height of a HCP unit cell is

5.715 A

0. What is the volume of the unit cell in cubic angstrom units ?

A) 91 B) 182 C) 273 D) 82.5

7. In a solid AB having the NaCl structure, A atoms are in fcc and B atoms occupy octahedral voids. If all the face centered atoms along one of the axes (four fold axes or facial axes) are removed, then the resultant stoichiometry of the solid is

A) 2

AB

B)

A B

₂ C)

A B

_{4 3} D)

3 4

8. In a compound

PQ O

_{2 4} having inverse spinel structure, oxide ions are arranged in CCP and cations P are present in octahedral voids. Cations, Q are equally distributed among octahedral and tetrahedral voids. The fraction of octahedral voids occupied is,

A)

1

4

B)

1

2

C)

1

3

D)

2

3

9. The packing efficiency of the two-dimensional square unit cell shown below is

(A) 39.27% (B) 68.02% (C) 74.05% (D) 78.54%

10. _{A sample of wustite FexO contains one Fe(III) for every three Fe(II). Calculate the value of x.}

(A) 2/5 (B) 19/5 (C) 8/9 (D) 16/15

11 . Iron crystallises in several modifications. At about 910oC, ‘bcc’ form (called form) undergoes transition to form with ‘fcc’ lattice. Assuming that the distance between the nearest neighbours is the same in the two forms at the transition temperature, then the ratio of the density of -iron to that of -iron at the transition temperature is.

(a) 2.12 (b) 3.2 (c) 4.3

. (d) 1.1

12. An element crystallises in fcc lattice. If the effective number of atoms of the element per unit cell in the crystal is decreased by 0.25% due to Schottky defect then the density of crystal is (At. Wt. = 50 and edge length = 0.50 nm)

(A)

2g / cc

(B)

2.6 g / cc

(C)

3.06 g / cc

(D)

4 g / cc

13.

14. An element crystallizes in bcc as well as fcc having edges 300 and 400 pm respectively. The ratio of their densities would be

A) 1.18 B) 2.28 C) 3.38 D) 4.48

15. Oxide ions are arranged in ccp (Cubic Close Packing) in a spinel-structure. One eighth of tetrahedral holes occupied by

A

2ions and one half of the octahedral holes are occupied by

B

3. The volume unoccupied in unit cell of this spinel approximately is

Single Answers

1 D 2 D 3 A 4 B 5 B 6 B

7 D 8 B 9 D 10 C 11 D 12 B

13 D 14 A 15 D

One or more than one answer type questions:

1. The data given below is used to find the type of cubic lattice to which the crystal belong.

Ag Al Cu Na

a (pm) 407.7 405 361 424

 (g cm-3_{) 10.5 2.7 8.92 1.002}

At. mass (gm) 108 27 63.5 23 Which of the above crystallizes in FCC unit cell

(A) Ag (B) Al

(C) Cu (D) Na

2. Which of the following is/are correct for Cs Cl type crystal: (A) It is ideal BCC structure.

(B) Cs+ _{and Cl} _{both ions forms a simple cubic lattice which inter penetrate each other.}

(C) Cs+ _{ions are at the body centre of Cl} _{unit cell}

(D) Cl ions are at the body centre of Cs+ _{unit cell.}

3. Select right statement(s)

A)

6Cs

ions occupy the second nearest neighbour locations of a

Cs

ion in the unit cell of CsCl B)

Each sphere has a share of six voids in two dimensional hexagonal close packed layer C)

If the radius of cations and anions are

0.3

A and

0

0.4

A

0 then coordination number of cation in the crystal is 6. the crystal is 6.

D) In AgCl, the silver ion is displaced from its lattice position to an interstitial position such that the defect is called a Frenkel defect.

4. Which of the following is(are) correct statement(s)?

(A)Schottky defect have no effect on the physical properties of solid

(B) Greater is the number of F-centres, greater is the intensity of color developed (C) Frenkel defect is a dislocation defect

(D) A compound may have both Frenkel and Schottky defect

5. If in NaCl crystal, two ‘F-centres’ are present per unit cell then the possible formula per unit cell is/are

(A) Na4Cl3.75 (B) Na4Cl3 (C) NaCl _{(D) Na4Cl3.375} 6. Which of the following statements are correct

a) In body centred cubic packing, packing efficiency is 68% b) A cubic system has 23 elements of symmetry

c) Free space in FCC packing is 74%

7. Identify the correct statements.

A)

Frenkel defect appears in AgI, ZnS and AgBr. B)

Zinc blend structure is obtained when

Zn

2occupies half tetrahedral sites. C)

Ferrimagnetism is in the alignment of magnetic moments but not in

D) _{In antifluorite structure cations are arranged in CCP while anions occupy all the tetrahedral voids.}

8. Pick out the correct statement(s)?

A) Due the presence of F- centres in crystals, the crystal attains paramagnetic character.

B) Frenkel defect is a dislocation defect.

C) In case of diamond that follows zinc blende structure the number of carbon atoms per unit cell is four

D) Due to Schottky defect in crystals, the electrical neutrality is not affected

9. Among the following, identify the correct statements(s)?

A) _{The number of atoms in 100g of an FCC crystal with density,} 3

10

gcm

&





 cell edge at 200pm are

5 10



24

B) Sr-90 radio isotope (

T

_1/2



27

years

) obtained as one of the fission products of uranium-235. The time required for 1.00g of the isotope to be reduced to 0.2g by decay is



63 years.

C) The rate of uncatalyzed reaction at 1270_{C is equal to that of the catalyzed reaction at 27}0_{C. The catalyst lowers}

the activation ornery by 25%.

D)

Barium permanganate



₄



2

Ba MnO









oxidises ferrous oxalate in

dil H SO

.

2 4medium and itself is reduced to 4

MnSO

. The volume of 0.1M

Ba MnO



_{4 2}



is needed to oxidise 50ml. 0.2M ferrous oxalate in acidic medium is 30ml.

One or more than one Answers

1 ABC 2 BCD 3 AD 4 BCD 5 ABD 6 AB

7 ABC 8 ABD 9 ABCD

Comprehensions type questions: Passage –1

An ionic solid adopts definite structure while getting crystallised. Various types of crystallise structures were identified based on arrangemnet of ions in defferent planes like h.c.p, f.c.c and b.c.c etc.

1. In an FCC lattice of ‘X– ’ ions the following plane is found.

A

B

If the radius of each ion is 2A0, what is the distance between the centres of ions labelled A and B?

A)

4 6A

0 B)

2 3A

0 C)

4 3A

0 D)

2 6A

0

2. A metal adopts FCC crystal structure. What is the ratio of the densities of the metal and metal atom?

A)

2

16

B)

3 2



C)

3

8 2



D)

3

8 2

3. Which type of plane is not present in an FCC lattice of a salt MX? [X = O, M = ]

A) B)

C) D)

Passage - 3

The X-ray diffraction by crystals is a powerful tool to elucidate their structure, W.L. Bragg and W.H. Bragg used this technique to study the crystal structure of solids. The formulated a mathematical relationship to determine the interatomic distance from X-ray diffraction patterns. The relationship is known as Bragg equation and can be represented as

n

 

2 sin

d



Where d is the distance between the successive atomic planes of the crystal,



is the wavelength of incident X-rays, n is the order of diffraction and



is the angle of incidence of the X-rays.

7. Which of the following statements is not correct?

(A) A crystal acts as a grating for the incident X-rays

(B) The distances between the atomic layers in a crystal are of the same order as the wavelength of X-rays

(C) If the diffracted waves are in the same phase, a series of dark spots is obtained on the photographic plate

(D) A crystal lattice may be supposed to be made up of regular layers or planes of the structural units situated at same distances from one another.

8. The X-rays reflected by two successive planes in a crystal are in phase with one another when the difference in their paths is equal to

(A) A fractional number of wavelengths

(C) A negative number of wavelengths

9. The diffraction of X-rays by a crystal is possible only when

(A)

 

2d

(C)

 

2d

Paragraph – 4

A crystal may have several type of defects. Some of these are Schottky defect, metal excess defect. Frankel defect etc. In Schottky defect, some of the lattice poi

when a cation leaves its lattice site and occupies an intestinal site. In the meatal excess defect due to anion vacancy, an anion is missing from its lattice site and the hole thus created is

10. Which of the following is a stoichiometric defect?

(A) Metal excess defect due to anion vacancies

(B) Cation deficiency defect

(C) Schottky defect

11. Which of the following statements is/are correct?

(A) Schottky defect affects the dielectric constant of the crystal

(B) Frankel defect decreases the density of the crystal

(C) Pink colour of LiCl crystals is due to electrons trapped in anion vacancies

(D) Frenkel defect is common in highly ionic comp anions of almost equal sizes

12. Which of the following statements is not correct for the electrons trapped in anion vacancies?

(A) The electrons trapped in anion vacancies in a crystal are called

(B) The trapped electrons are localised

(C) The trapped electrons are delocalised

(D) F-centres impart violet colour to KCl crystal.

Paragraph – 5

The density of any crystal structure can be calculated by mass contained in unit cell per is no. of molecules per unit cubic cell of edge length a, the mass per unit volume of cell is

A

M

Mass

Z

N



_



_

 

_

_

_





Density 3

ZM

a N



13. _{Correct expression for density of unit cell of CsCl}

rays reflected by two successive planes in a crystal are in phase with one another when the difference in

A fractional number of wavelengths (B) An integral number of wavelengths

A negative number of wavelengths (D) Zero

rays by a crystal is possible only when

(B)

 

2d

(D)

 

2d

A crystal may have several type of defects. Some of these are Schottky defect, metal excess defect. Frankel defect etc. In Schottky defect, some of the lattice points in the crystal lattice are unoccupied. Frenkel defect arises when a cation leaves its lattice site and occupies an intestinal site. In the meatal excess defect due to anion vacancy, an anion is missing from its lattice site and the hole thus created is occupied by an electron.

Which of the following is a stoichiometric defect?

Metal excess defect due to anion vacancies

(D) F centre defect

Which of the following statements is/are correct?

Schottky defect affects the dielectric constant of the crystal

(B) Frankel defect decreases the density of the crystal

Pink colour of LiCl crystals is due to electrons trapped in anion vacancies

(D) Frenkel defect is common in highly ionic compounds with high coordination number and having cations and

Which of the following statements is not correct for the electrons trapped in anion vacancies?

The electrons trapped in anion vacancies in a crystal are called F-centres

(B) The trapped electrons are localised

The trapped electrons are delocalised

centres impart violet colour to KCl crystal.

The density of any crystal structure can be calculated by mass contained in unit cell per is no. of molecules per unit cubic cell of edge length a, the mass per unit volume of cell is

3 A

ZM

a N

Correct expression for density of unit cell of CsCl in terms of radius of

Cs



 

r

_{ and radius of}

rays reflected by two successive planes in a crystal are in phase with one another when the difference in

A crystal may have several type of defects. Some of these are Schottky defect, metal excess defect. Frankel defect nts in the crystal lattice are unoccupied. Frenkel defect arises when a cation leaves its lattice site and occupies an intestinal site. In the meatal excess defect due to anion

occupied by an electron.

ounds with high coordination number and having cations and

Which of the following statements is not correct for the electrons trapped in anion vacancies?

The density of any crystal structure can be calculated by mass contained in unit cell per unit volume. If Z is no. of molecules per unit cubic cell of edge length a, the mass per unit volume of cell is

and

N

_A (Avogadros number) is (density is in

g cm

/

3) A)

 

3 3 3 2 CsCl A M r_ r_ N      B)

 

30 3 3 10 2 3 2( CsCl A M r_ r_ N      



C)

 

3 3 ₃₀

3

2(

10

CsCl A

M

r

_

r

_

N















D)

 

3 3

2

3

2(

CsCl A

M

r

_

r

_

N











14. A metal crystallizes into two type of crystal unit cells, face centered cubic (fcc) and body centre cubic (bcc) whose unit cell lengths are 2 pm and 2.8 pm respectively. Ratio of densities of fcc and bcc will be

A) 5.49 B) 7.23 C) 6.84 D) 4.58

15.

The number of atoms in 100 g of a bcc crystal with density

d



10

g cm

/

3and cell edge = 200 pm is

A)

_{4.5 10}



25 B)

_{2.5 10}



24 C)

₁₀

24 D)

4

N

_A

Paragraph – 6

A cubic unit cell is said to be primitive if all the eight corners of the cube are occupied by the same atoms and these atoms are not found anywhere else in the cube. The rank of the primitive cubic unit cell is 1. The packing fraction is 0.52. In body centered cubic unit cell, the rank is 2 and packing fraction is 0.68. In face centered cubic unit cell,rank is 4 and packing fraction is 0.74. In hexagonal primitive unit cell rank is 6 and packing fraction is 0.74.

16. CsCl has bcc arrangement where Cl- _{ions occupy the corners and Cs} + _{ions occupy the body centre with a unit cell}

edge length of 400 pm. The shortest distance between Cs + _{and Cl}- _{ions is}

A) 100 pm B) 346.4 pm C) 500 pm D) 600 pm

17.

Edge length M + _X- _{(fcc structure) is}

6.2A

0_{. Assuming M} + _{- X}- _{contact along the cell edge, radius of X}- _{ion is}



0



1.6A

M

r

_



A)

_1.5A

0 B)

_5.0A

0 C)

_2.0A

0 D)

_5.5A

0

18. A compound is formed by elements A and B. This crystallized in

cubic structure when atoms A are at the body center of the cube and atoms B are at the corners. The simplest formula of compound is

A) AB B) AB2 C) A2B D) AB4

Paragraph – 7

When atoms are arranged in ABC ABC type of packing or ABAB type of packing, some space is left in between the atom which is known as voids. Depending upon the situation, voids can be classified as triangular, tetrahedral, octahedral or cubic. For

example;

Void shown in the figure is triangular void because it is formed by touching 3 atoms.

19. If radius of sphere is 200 pm then ideal radius of triangular voids is:

A) 31 pm B) 45 pm C) 62 pm

20.

If for a particular compound AB, radius of

then location of A + _{ion in the crystal and % occupancy respectively is:}

A) Octahedral void 100% B) Tetrahedral, 100%

C) Tetrahedral, 50% D) Octahedral, 50%

21. Formula of a compound formed by A, B and C in

present in 25% of the tetrahedral voids and C is present in all the remaining voids (tetrahedral as well as octahedral) is:

A) AB2C2 B) A2BC5 C) ABC5

Paragraph – 8

Atoms / ions in a crystal have a perfect arrangement only at absolute zero. At room temperature, crystals generally posses some defects which influence the properties of the crystals. In some cases, we carry out doping to get the desired properties in the

22. Which of the following will produce p-type semi conductor?

A) Silicon doped with phosphorus

C) Gallium doped with arsenic

23.

Analysis shows that nickel has formula respectively will be

A) 96% & 4% B) 97% & 3%

24.

NaCl is doped with

SrCl

₂in the moles ratio of of NaCl will be

A) 23

6.023 10



B)

6.023 10



17

Void shown in the figure is triangular void because it is formed by touching 3 atoms.

If radius of sphere is 200 pm then ideal radius of triangular voids is:

D) 90 pm

If for a particular compound AB, radius of A + _{is 80 pm and radius of is 200 pm}

ion in the crystal and % occupancy respectively is:

Tetrahedral, 100%

Octahedral, 50%

Formula of a compound formed by A, B and C in which . A is arranged in ccp, B is present in 25% of the tetrahedral voids and C is present in all the remaining voids

D) A2B5C

Atoms / ions in a crystal have a perfect arrangement only at absolute zero. At room temperature, crystals generally posses some defects which influence the properties of the crystals. In some cases, we carry out doping to get the desired properties in the crystal.

type semi conductor?

B) Germanium doped with arsenic

D) Germanium doped with gallium.

Analysis shows that nickel has formula 0.98

Ni

O

. The percentage of Ni present as

Ni

2and

C) 98% & 2% D) 99% & 1%

the moles ratio of

10

6

:1

the concentration of cation vacancies per mole

17 C) 18

1.2046 10



D)

6.023 10



18

Atoms / ions in a crystal have a perfect arrangement only at absolute zero. At room temperature, crystals generally posses some defects which influence the properties of the crystals. In some cases,



and

Ni

3

Paragraph – 9

Ionic compounds occur in crystalline forms. Ionic crystals are made of cations and anions. These ions are arranged in 3 dimensional array to form an aggregate of the type (A+B–). If one of the ions is much larger than the other, it is common for larger ions alone to approach a closest packed structures and smaller ions to fit into holes in this structure

25. For magnesium telluride , crystal radius of cation and anion are 0.65Å and 2.21Å, then what is the correct arrangement ?

(A) Mg constitutes c.c.p. lattice and Te is present in octahedral voids

(B) Mg constitutes c.c.p. lattice and Te is present in tetrahedral voids

(C) Te constitutes c.c.p. lattice and Mg is present in octahedral voids

(D) Te constitutes c.c.p. lattice and Mg is present in tetrahedral voids

26. A fcc system contains 4 octahedral and 8 tetrahedral voids. Nearest distance possible between octahedral and tetrahedral void is (a is edge length of unit cell)

(A) (B) (C) (D)

Paragraph – 10

Many solids crystallize in various possible ways. Most metals choose ABAB packing and many choose ABCABC packing both having similar packing fraction. During packing of atoms, atoms develop different voids whose shape depends on relative packing.

27. Which metallic block acquire more number of atoms on surface of crystal with equal area?

(A) Circular (B)Square

(C) Rectangular (D) Hexagonal

28. Maximum number of nearest

Cl



ions close to Na+ _{ion in NaCl crystal can be}

(A) 4 (B) 6 (C) 8 (D) 12

29. Number of triangular voids present per unit face centered unit cell is (A) 0 (B) 12 (C) 24 (D) 32

Passage -11

A cubic system has 9 planes of symmetry, 13 axis of symmetry and 1 centre of symmetry. The number of nearest neighbors with which a given sphere is in contact is called co-ordination number. Co-ordination number in HCP and CCP arrangements is 12. while in BCC arrangement coordination number is 8.

co-ordination number can be predicted by radius ratio rules. When

r

0.155, 0.225

r

 



and 0.414, the

coordination number is 3,4 and 6, respectively. In simple cubic cell or primitive cubic, B.C.C. and F.C.C. the values of packing fraction are 0.52, 0.68 and 0.74, respectively. Point defects are due to missing or misplaced cations and anions. In schottkey defect equal number of cations and anions are missed while in Frankel defect cations displace from their position and enter void space.

30. How many nearest neighbors are there in an atom or ion for an octahedral hole of a closed packed structures :

a) 12 b) 8 c) 6 d) 4

31. If the radius of

Na

 is 75pm and that of

Cl

 is 181pm then which of the following is correct ?

a

16

3

a

4

3

_a

4

2

a

16

2

a) coordination number of

Na

 is 8 b) coordination number of

Na

 is 6 c) Length of unit cell is 480 pm d) Length of unit cell is 380 pm

32. If

r

r

 

lies between 0.225 and

0.414,

cations occupies :

a) Tetrahedral void b) Octahedral void

c) Trigonal void d) Cubic void

Passage-12

In a cryrtal lattice the number of atoms per unit cell is 1 for simple cubic, 4 for fcc and 2 for bcc respectively. The coordination number is 6 for simple cubic, 8 for bcc and 12 for fcc. Similarly the density of a crystal is given

by the formula; density

;

A

ZM

N V



where

Z

is the number of particles per unit cell, M the molar mass of solid, V the volume of the unit cell and

N

_A the Avogadro Number. The ratio of the volume of the unit cell that is occupied by spheres of the unit cell to the total volume of the unit cell is called packing fraction. For simple cubic, BCC and FCC the packing fraction is 0.52, 0.68 and 0.74 respectively.

33. A cubic crystalline solid contain A atoms at the corners, B atoms at the face centers and C atoms at the edge centers. Then the simplest formula of the compound

a)

AB C

_{2 3} b)

AB C

_{3 3} c)

AB C

₂ d)

A B C

_{2 2 3}

34. The unit cell of an element of atomic mass 96 and density

10.3 /

g cc

is a cubic with edge length of 314pm. Then the type of crystal lattice is

a) simple cubic b) FCC c) BCC d) HCP

35. If the radius of

M

 is 169pm and that of

X

 is 181pm then the coordination number of

M

 is

a) 4 b) 6 c) 8 d) 12

Passage–13

Stoichiometric compounds are those where the number of the different types of atoms or ions present in exactly the ratios indicated by their chemical formulae, otherwise non stochiometric compounds are formed. The schottky defect involves absence of one positive and one negative ion. Frenkel defect consists of a vacant site and the ion is now occupied an interstial site. An F-center is formed when an electron is occupied by an electron. Metal deficiency in caused by missing positive ion or caused by a negative ion in interstitial gap.

36. The incorrect statement about schottky defect

a) the electro neutrality of crystal will not change

b) density of crystal will decrease

c) crystals with large difference in size of cation and anion will show this defect

d) electric conductivity of crystal will increase

a) density of the crystal will not change.

b) Crystals with similar radius of cation & anion will show this type of defect

c)

NaCl CsCl

,

type crystals will show this defect

d) Electric conductivity will not chage.

38. Which of the following defect if present will not change the density of the crystal

a) Frenkel defect b) schottky defect c) F-Centers d) metal excess

Passage–14

In HCP as well as CCP, only 74% of the available space is occupied by spheres. The remaining space is vacant and constitute interstial voids or spaces. There are two types of interstitial space, tetrahedral and octahedral voids, in three dimensional close packing. In a close packing, the number of tetrahedral voids is double the number of spheres. Radius of the tetrahedral voids relative to the radius of the sphere is 0.225, that is, for tetrahedral voids

void sphere

r

0.225

r



.In a close

packing, the number of octahedral voids is equal to the number of spheres. Radius of the octahedral void relative to

the radius of the sphere is 0.414 that is, for octahedral void sphere

void

r

0.414

r



.

39. In a compound of

XY O

_{2 4}, oxide ions are arranged in CCP and cations X are present in octahedral voids. Cations Y are equally distributed between octahedral and tetrahedral voids. The fraction of the octahedral voids occupied is

A)

1

2

B)

1

4

C)

1

8

D)

1

6

40.

In a solid, oxide ions are arranged in CCP cations A occupy

1

6

of the tetrahedral voids and cations B occupy

1

3

of the

octahedral voids.The formula of the compound is

A)

ABO

₃ B)

AB O

_{2 3} C)

A BO

_{2 3} D)

A B O

_{2 2 3}

41. Mineral having the formula

AB

₂crystallizes in cubic packed lattice, with A atoms occupying the lattice points. The coordination number of A atoms, that of B atoms and percentage of tetrahedral voids occupied by B atoms are respectively.

A) 8, 4, 100% B) 2, 6, 75% C) 3, 1, 25% D) 6, 6, 50%

Passage–15

Diamond is a crystalline allotrope of carbon, which crystallizes in a 3-dimensional lattice. Each carbon forms four bonds with other carbon atoms. The unit cell of the diamond lattice can be thought of containing carbon atoms present at all CCP positions as well in alternate tetrahedral voids. Assuming contact between nearest atoms, answer the following .

42. Number of carbon atoms per unit cell of diamond structure is

a) 4 b) 8 c) 12 d) data insufficient

43. What is the fraction of length covered along the body diagonal of the cubic unit cell by carbon atoms?

a) 0.50 b) 0.34 c) 0.75 d) 0.25

44. How much fraction of area of one face is covered by atoms?

a)

3

32



b)

6

32



c)

9

32



d)

3

64



Comprehensions Answers 1 A 2 B 3 D 4 A 5 A 6 C 7 C 8 B 9 A 10 C 11 C 12 B 13 C 14 A 15 B 16 B 17 A 18 A 19 B 20 D 21 B 22 D 23 A 24 B 25 D 26 B 27 D 28 B 29 D 30 C 31 B 32 A 33 B 34 C 35 C 36 C 37 A 38 A 39 A 40 A 41 A 42 43 44

Matching answer type questions:

1.

Column-I Column-II

a) p) Colour

c) r) Density is less than perfect crystal

d) s) Increase in dielectric constant of the

crystal

(t) Size of anions and cations differ much in their size and ions have low co-ordination no. and ions have low co-ordination no.

3. Match the following

Column – I : Formula with cation : anion coordination; packing for the given solids in one ccp in the remaining three hcp.

Column – II : Total no. of holes occupied per unit cell.

Column – I Column – II

a)

MX

₂



6 : 3



p) Half tetrahedral voids are occupied.

b)

MX 4 : 4





q) one third octahedral voids are occupied

c)

M X 6 : 4

_{2 3}





r) Half octahedral voids are occupied

d)

MX 6 : 2

₃





s) Two thirds octahedral voids are occupied

5. Match the following :

Column I Column II

(a)

2 4

MgAl O

(p) paramagnetic substance

(b)

3 4

Fe O

(q) ferrimagnetic

(c) Ferrite (r) spinel substance

(d) CuO (s) inverse spinel

Column I Column II (a)

_NaCl

(p) Schotky defect (b)

_ZnO

(q) Stoichiometric defect (c)

0 92

.

Fe

O

(r) Point defect

(d)

_AgCl

(s) Non-stoichiometric defect

7. Match the following

Column –I Column –II

A) NaCl p)

₉₀

o

a



b



c and













B) CaSO4 q)

_a

_

_b

_

_c

and













90

o C) BaSO4 r)

_a

_

_b

_

_c

_and

_

_

_

_

_

_

₉₀

o D) 4

5

2

CuSO



H O

s)

_a

_

_b

_

_c

_and

₉₀

o













8. Match the following

List – I List – II

A)Packing fraction = 0.68 _{p)Axial angles,} 0

90













B) Cubic system q) B.C.C unit cell

C) Triclinic system r) F.C.C. unit cell

D) Packing fraction = 0.74 _{s) Axial angles} 0

90













11. Match the following

Column – I Column – II

A) Diamagnetic materials p) TiO

B) Paramagnetic material q) NaCl

C) Ferromagnetic materials r)

Fe

₃

O

₄ D) Ferrimagnetic materials s)

CrO

₂

12. Match the Following:

Column I Column II

(a) Simple cubic and face-centred cubic

(b) cubic and rhombohedral

(c) cubic and tetragonal

(d) hexagonal and monoclinic

Matching Answers 1 A – R B – QST C – P D - P 2 A-QR B-S C-QR D-P 3 7 A-Q B-P C-R D-S 8 A-QS B-QRS; C-P ; D-RS 9

Integer answers type questions:

3. _{The coordination number of}

_Na



in NaCl is x and that of Na in sodium metallic lattice is y, the difference between y and x is

4. Iron crystallizes in two body centered cubic lattices the

face centered cubic β-form between those two temperatures. If the maximum ratio of radius of foreign particle

occupying a hole in the face of a body centered cubic unit cell to the host iron radius is ‘a’ is

5.

_{M X}

 

crystallies as fcc structure. Edge length is 3.2 A along the cell edge, radius of

M



ion is

x

A

7. In rutile, the coordination number of the anion is

8. The sulphide of a metal M(At wt 58) has a cubic structure having four formula units per unit cell. If its density is 4.27g/ccand the edge length is 6.93 A0_{, the number of atoms present per formula unit are}

9. In diamond, effective no. of carbon atoms along

Integer Answers

a = b = c and













90

0

(q) are two crystal systems

(r) have only two crystallography angles of 90o

(s) belong to same crystal system

A – R B – P C – S D – Q 4 A – S B – R C – P D - Q 5 A-R B-QS C-QR D-P A-Q; B-R ; C-S; D-PQ 10 A-R B-S C-P D-PQ 11 A-Q B-P C-S D-R

in NaCl is x and that of Na in sodium metallic lattice is y, the difference between y

Iron crystallizes in two body centered cubic lattices the



-form below 750°C and γ-form above 1400°C and in a form between those two temperatures. If the maximum ratio of radius of foreign particle

occupying a hole in the face of a body centered cubic unit cell to the host iron radius is

4 a

a

crystallies as fcc structure. Edge length is 3.2 A0_{. Radius of anion is 1.4 A}0_{. Assuming}

0 1

10

x





A

. The value of

' x '

is In rutile, the coordination number of the anion is

The sulphide of a metal M(At wt 58) has a cubic structure having four formula units per unit cell. If its density is , the number of atoms present per formula unit are

In diamond, effective no. of carbon atoms along any body diagonal of unit cell is n/4. What is the value of n. 6 _{A PQR} B RS C RS D QR 12 A-PS B-Q C-Q D-PR

in NaCl is x and that of Na in sodium metallic lattice is y, the difference between y

form above 1400°C and in a form between those two temperatures. If the maximum ratio of radius of foreign particle

4 a

a

a



, then value of

. Assuming

M





X

contact

The sulphide of a metal M(At wt 58) has a cubic structure having four formula units per unit cell. If its density is

1 8 2 4 3 2 4 6 5 2 6 7