Solid State

When molten zinc is cooled to solid state it assmes hcp structure. Then the number of nearestt neighbours of zinc atoms will be [ AIPMT / NEET 2001]
1. 4
2. 6
3. 8
4. 12
The pycnometric density of sodium chloride crystal is $2.165 \times 10^{3} k g m^{- 3}$ while its X-ray density is $2.178 \times 10^{3} k g m^{- 3}$ . The fraction of the unoccupied sites in sodium chloride crystal is [AIPMT / NEET 2003]
1. 5.96
2. $5.96 \times 10^{- 2}$
3. $5.96 \times 10^{- 1}$
4. $5.96 \times 10^{- 2}$
With which one of the following element silicon should be doped so as to give p-type semiconductor ? [AIPMT / NEET 2005]
1. As
2. Se
3. B
4. Ge
CsBr crystallises in a body centred cubic lattice. The net cell length is 436.6 pm. Given that the atomic mass of Cs = 133 and that of Br = 80 amu and Avogadro number being $6.02 \times 10^{23} m o l^{1}$ , the density of CsBr is [AIPMT / NEET 2006]
1. $8.25 g / c m^{3}$
2. $4.25 g / c m^{3}$
3. $42.5 g / c m^{3}$
4. $0.425 g / c m^{3}$
Which of the following statements is not correct ? [AIPMT / NEET 2007]
1. Molecular solids are generally volatile
2. The number of carbon atoms in a unit cell of diamond is 4
3. The number o Bravais lattices in which a crystal can be categorized is 14
4. The fraction of the total volume occupied by the atoms in a primiutive cell is 0.48
If NaCl is dropped with $10^{- 4}$ mole % of $S r C l_{2}$ , the concentration of cation vacancies will be [AIPMT / NEET 2007]
1. $6.02 \times 10^{16} m o l^{- 1}$
2. $6.02 \times 10^{17} m o l^{- 1}$
3. $6.02 \times 10^{14} m o l^{- 1}$
4. $6.02 \times 10^{15} m o l^{- 1}$
The faction of total volume occupied by the atoms present in a simple cube is [AIPMT / NEET 2007]
1. $\frac{π}{3 \sqrt{2}}$
2. $\frac{π}{4 \sqrt{2}}$
3. $\frac{π}{4}$
4. $\frac{π}{6}$
If 'a' stands for the edge length of the cubic systems:simple cubic, body-centred and face-centred, then the ratio of radii of the spheres in these systems will be respectively [AIPMT / NEET 2008]
1. $\frac{1}{2} a : \sqrt{3} a : \frac{1}{\sqrt{2}} a$
2. $\frac{1}{2} a : \frac{\sqrt{3}}{a} a : \frac{\sqrt{2}}{2} a$
3. $\frac{1}{2} a : \sqrt{3} a : \sqrt{2} a$
4. $\frac{1}{2} a : \frac{\sqrt{3}}{4} a : \frac{1}{2 \sqrt{2}} a$
Percentage of free space in a body-centred cubic unit cell is [AIPMT / NEET 2008]
1. 32%
2. 34%
3. 28%
4. 30%
Lithium metal crystallizes in a body-centred cubic crystal. If the length of the side of the unit cell if lithium is 351 pm, the atomic radius of the lithium will be [AIPMT / NEET 2009]
1. 300.5 pm
2. 240.8 pm
3. 151.8 pm
4. 75.5 pm
AB crystallises in a bec lattice with edge length 'a' equal to 387 pm. The distance between two oppositively charged ions in the lattice is [AIPMT / NEET 2010]
1. 335 pm
2. 250 pm
3. 200 pm
4. 300 pm
The number of octahedral void(s) per atom present in a cubic close-packed structure is [AIPMT / NEET 2012]
1. 2
2. 4
3. 1
4. 3
A metal crystallizes with a face-centred cubic lattice. The edge of the unit cell is 408 pm. The diameter of the metal atom is [AIPMT / NEET 2012]
1. 144 pm
2. 204 pm
3. 288 pm
4. 408 pm
Structure of a mixed oxide is cubic closed-packed (ccp). The cubic unit cell of mixed oxide is composed of oxide ions. One-fourth of the tetrahedral voids are occupied by a monovalent metal B. The formula of the oxide is [AIPMT / NEET 2012]
1. $A B O_{2}$
2. $A_{2} B O_{2}$
3. $A_{2} B_{3} O_{4}$
4. $A B_{2} O_{2}$
A metal has an fcc latticed. The edge length of the unit cell is 404 pm. The density of the metal is $2.72 g c m^{- 3}$ . The molar mass of the metal is ( $N_{A} A v o g a d r o' s c o n s \tan t = 6.2 \times 10^{23} m o l^{- 1}$ ) [AIPMT / NEET 2013]
1. $30 g m o l^{- 1}$
2. $27 g m o l^{- 1}$
3. $20 g m o l^{- 1}$
4. $40 g m o l^{- 1}$
The number of the carbon atoms per unit cell of diamond unit cell is [AIPMT / NEET 2013]
1. 8
2. 6
3. 1
4. 4
If 'a' is the length of the side of a cubic unit cell the distance betwen the body-centred atom and one corner aton in the cube will be [AIPMT / NEET 2014]
1. $\frac{2}{\sqrt{3}} a$
2. $\frac{\sqrt{3}}{2} a$
3. $\frac{4}{\sqrt{3}} a$
4. $\frac{\sqrt{3}}{4} a$
A given metal crystallises out with a cubic structure having edge length of 361 pm. If there are four metal atoms in one unit cell, what is the radius of one atom ? [AIPMT / NEET 2015]
1. 80 pm
2. 108 pm
3. 40 pm
4. 127 pm
The vacant space in bcc lattice unit cell is [AIPMT / NEET 2015 Re]
1. 23%
2. 32%
3. 26%
4. 48%
Lithium has a bcc structure. Its density is $530 k g m^{- 3}$ and its atomic mass is $6.94 g m o l^{- 1}$ . Calculate the edge length of a unit cell of lithiujm metal. ( $N_{A} = 6.02 \times 10^{23} m o l^{- 1}$ ) [AIPMT / NEET 2016 Phase-I]
1. 2643 pm
2. 154 pm
3. 352 pm
4. 527 pm
The ionic radii of $A^{+}$ and $B^{-}$ ions are $0.98 \times 10^{- 10}$ and $1.81 \times 10^{- 10}$ m. The co-ordination number of each ion in AB [AIPMT / NEET 2016 Phase-I]
1. 2
2. 6
3. 4
4. 8
The three states of matter are solid, liquid and gas. Which of the following statement is/are true about them ? [AIIMS 2001]
1. Gases and liquids have viscosity as a common property
2. The molecules in all the three states possess random translationalo motion
3. Gases cannot be converted into solids without passing through the liquid phase
4. Solids and liquids have vapour pressure as a common property
Which of the following ferroelectric Compound ? [AIIMS 2002]
1. $B a T i O_{3}$
2. $K_{4} [F e {(C N)}_{6}]$
3. $P b_{2} O_{3}$
4. $P b Z r O_{3}$
The solid NaCl is a bad conductor of electricity since [AIIMS 2003]
1. solid NaCl there are no ions
2. solid NaCl is covalent
3. in solid NaCl there is no velocity of ions
4. in solid NaCl there are no electrons
In graphite, carbon atoms are joined together due to [AIIMS 2004]
1. ionic bonding
2. van der Walls forces
3. metallic bonding
4. covalent bonding
Example of unit cell with crystallographic dimensions $a \neq b \neq c, α = γ = 90 °, β \neq 90 °$ is [AIIMS 2005]
1. calcite
2. graphite
3. rhombic sulphur
4. monoclinic sulphur
If 'Z' is the numberr of atoms in the unit cell that represents the closest packing sequence - - - A B C A B C - - - , the number of tetrahedral voids in the unit cell is equal to [AIIMS 2005]
1. Z
2. 2 Z
3. $\frac{Z}{2}$
4. $\frac{Z}{4}$
An $A B_{2}$ type structure is found in [AIIMS 2006]
1. NaCl
2. $A l_{2} O_{3}$
3. $C a F_{2}$
4. $N_{2} O$
An example of a body cube is [AIIMS 2007]
1. sodium
2. magnesium
3. zinc
4. copper
In a face centrred cubic cell, an atom at the face contributes [AIIMS 2008]
1. $\frac{1}{4}$ part.
2. $\frac{1}{8}$ part.
3. 1 Part.
4. $\frac{1}{2}$ part.
Sodium metal; crystallizes as a body centred cubic lattice with the cell edge 4.29 A. What is the radius of the sodium ? [AIIMS 2009]
1. $1.857 \times 10^{- 8} c m$
2. $2371 \times 10^{- 7} c m$
3. $3.871 \times 10^{- 8} c m$
4. $9312 \times 10^{- 7} c m$
Potassium has a bcc structure with nearest neighbour distance 4.52 A. Its atomic weight is 39. Its density will be ( $i n k g m^{- 3}$ ) will be [AIIMS 2010]
1. 454
2. 804
3. 852
4. 908
Body centred cubic lattice has a co-ordination number of [AIIMS 2011]
1. 4
2. 8
3. 12
4. 6
What is the co-ordination number of sodim in $N a_{2} O$ [AIIMS 2012]
1. 6
2. 4
3. 8
4. 2
In a solid lattice the cation has a left a lattice site and located at an interstitial position, the lattice defect is [AIIMS 2013]
1. Interstitial defect
2. Valency defect
3. Frenkel defect
4. Schottky defect
An element ( atomic mass 100 g / mol ) having bcc structure has unit cell edge 400 pm. Then density of the element is [AIIMS 2015]
1. $10376 g / c m^{3}$
2. $5.188 g / c m^{3}$
3. $7.289 g / c m^{3}$
4. $2.144 g / c m^{3}$
If the pressure on a NaCl structure is increased, then its co-ordination number will [AIIMS 2015]
1. increase
2. decrease
3. remain the same
4. either decrease or remain the same
ASSERTION : No compound has both Schottky and Frenkel defects
REASON : Schottky defects change the density of the solid [AIIMS 2008]
1. If both the assertion and reason are true is a true explanation of the assertion
2. If both the assertion and reason are true but the reason is not the correct explanation of assertion.
3. If the assertion is true but reason is false.
4. If assertion is false but reason is true.
ASSERTION : In any ionic solid (MX) with Schottky defects, number of positive and negative ions are same.
REASON : Equal number of cation and anion vacancies are present. [AIIMS 2009]
1. If both the assertion and reason are true is a true explanation of the assertion
2. If both the assertion and reason are true but the reason is not the correct explanation of assertion.
3. If the assertion is true but reason is false.
4. If assertion is false but reason is true.
ASSERTION : Co-ordination number of CsCl changes fgrom 8 : 8 to 6 : 6 on heating.
REASON : The crystal structure of CsCl changes to NaCl on heating [AIIMS 2010]
1. If both the assertion and reason are true is a true explanation of the assertion
2. If both the assertion and reason are true but the reason is not the correct explanation of assertion.
3. If the assertion is true but reason is false.
4. If assertion is false but reason is true.
ASSERTION : Band gap ub gernanium is small.
REASON : The energy spread of each germanium atomic energy level is infinitesimally small. [AIIMS 2012]
1. If both the assertion and reason are true is a true explanation of the assertion
2. If both the assertion and reason are true but the reason is not the correct explanation of assertion.
3. If the assertion is true but reason is false.
4. If assertion is false but reason is true.
ASSERTION : Diamond is a precious stone.
REASON : Carbon atoms are tetrahedrally arranged in diamond. [AIIMS 2013]
1. If both the assertion and reason are true is a true explanation of the assertion
2. If both the assertion and reason are true but the reason is not the correct explanation of assertion.
3. If the assertion is true but reason is false.
4. If assertion is false but reason is true.
Choose the correct statements :
1. equivalent points in unit cells of a periodic lattice lie on a Bravais lattice
2. equivalent points in unit cells of a periodic lattice do not lie on a Bravais lattice
3. There are four Bravais in two dimensions
4. There are five Bravais in three dimensions
A crystalline solid have
1. Long range order
2. Short range order
3. Disordered arrangement
4. None of these
Among solids the highest melting point is established by
1. Covalent solids
2. Ionic solids
3. Pseudo solids
4. Molecular solids
Crystalline solids are
1. Sugar
2. Rubber
3. Plastic
4. Glass
A crystalline solid
1. Changes abruptly from solid to liquid when heated
2. Has no definite melting point
3. Undergoes deformation of its geometry easily
4. Has an irregular 3-dimensional arrangements
Amorphous solids are
1. Supercooled liquid
2. Liquid in real sense
3. Solid substance in real sense
4. Substance with definite melting point
The solid NaCl is a bad conductor of electricity since
1. in solid NaCl there are no ions
2. solid NaCl is covalent
3. in solid NaCl there is no velocity of ions
4. in solid NaCl there are no electrons
Graphite is a soft lubricant extremely difficult to melt. The reason for this anomalous behaviour is that graphite
1. is a non-crystalline substance
2. is an allotropic form of diamond
3. has molecules of variable molecular masses like polymers
4. has carbon atoms arranged in large plates of ring of strongly bound carbon atoms with weak interplate bonds
A match box exhibits
1. Cubic geometry
2. Orthorhombic geometry
3. Monoclinic geometry
4. Tetragonal geometry
Silica $(S i O_{2})$ can be crystalline as well as amorphous with the following properties :
I. It has high and sharp melting point
II. Crystalline
III. The $S i O \frac{2 -}{4}$ tetrahedral are randomly joined to give polymeric chains or three dimensional sheets.
1. II and III
2. Only III
3. I and III
4. I and II
The existence of a substance in more than one solid modifications is known as or any compound having more than two crystal structures is called
1. Polymorphism
2. Isomorphism
3. Allotrophy
4. Enantimorphism
Which of the following characteristics is/are possessed by non-polar molecular solids ?
1. They have low melting point and are usually in liquid or gaseous state at room temperature and pressure
2. Atoms or molecules are held by weak dispersion force or London forces
3. They are sof and non-conductors of electricity
4. All the above
Which is not a property of solids ?
1. Solids are always crystalline in nature.
2. Solids have high density and low compressibility
3. The diffusion of solids is very slow
4. Solids have definite volute
Which one of the following is the most correct statement ?
1. Brass is an interstitial alloy, while steel is substitutional alloy
2. Brass and steel are both substitutional alloys
3. Brass is the substitutional alloy, while steel is an interstitial alloys
4. Brass and steel are both interstitial alloys.
Na and Mg crystallize in bcc and fcc type crystals respectively, then the number of atoms of Na and Mg present in the unit cell of their respective crystals is
1. 4 and 2
2. 9 and 14
3. 14 and 9
4. 2 and 4
Which solid will have the weakest inter-molecular forces ?
1. Ice
2. Phosphorus
3. Napthalene
4. Sodium fluoride
Which of the following exists as covalent crystals in the solid state ?
1. Sulphur
2. Phosphorus
3. Iodine
4. Silicon
Which of the following statements is not true about amorphous solids ?
1. The constituent particles are arranged in a regular fashion containing short range as well as long range order.
2. When kept for a long time, they may become crystalline
3. They can be moulded by heating
4. They are isotrophic in nature.
The sharp melting point of crystalline solids compared to amorphous solids is due to
1. different arrangement of constituent particles in different directions
2. same arrangement of constituent particles in different directions
3. a regular arrangment of constituent particles observed over a sheet distance in the crystal lattice
4. a regular arrangment of constituent particles observed over a long distance in the crystal lattice
In graphite, carbon atoms are joined together due to
1. Covalent bonding
2. van der Waals' forces
3. Metallic bonding
4. Ionic bonding
Which of the following is a molecular crystal ?
1. Ice
2. NaCl
3. Graphite
4. SiC
Which type of solid crystals will conduct heat and electricity ?
1. Ionic
2. Metallic
3. Covalent
4. Molecular
The number of atoms per unit cell in a simple cubic, face-centered cubic and body-centered cubic are
1. 1,4,2
2. 4,1,2
3. 2,4,1
4. 4,8,2
The total number of lattice arrangements in different crystal system is
1. 3
2. 8
3. 7
4. 14
In a face centered cubic cell, the contribution of an atom at a face of the unit cell is
1. $\frac{1}{2}$
2. 1
3. 2
4. 3
A solid has a structure in which 'W' atoms are located at the corners of a cubic lattice 'O' atoms at the centre of edges and 'Na' atoms at the centre of the cube. The formula for the compound is
1. $N a W O_{2}$
2. $N a W O_{3}$
3. $N a_{2} W O_{3}$
4. $N a W O_{4}$
In a solid 'AB' having the NaCl structure, 'A' atoms occupy the corners of the cubic unit cell. If all the face-centered atoms along one of the axes are removed, then the resultant stoichiometry of the solid is
1. $A B_{2}$
2. $A_{2} B$
3. $A_{3} B_{4}$
4. $A_{4} B_{3}$
A substance $A_{X} B_{Y}$ crystallises in a face centered cubic (fcc) lattice in which atoms 'A' occupy each corner of the cube and atoms 'B' occupy the centres of each face of the cube. Identify the correct composition of the substance $A_{X} B_{Y}$
1. $A B_{3}$
2. $A_{4} B_{3}$
3. $A_{3} B$
4. composition cannot be specified
An element crystallises in fcc lattice having edge length 350 pm. Maximum radius of the atom which can be placed in the interstitial site witholut distorting the structure is
1. 58.55 pm
2. 117 pm
3. 51.23 pm
4. 83 pm
The number of atoms present in unit cell of amonoatomic substance of simple cubic lattice is
1. 1
2. 3
3. 2
4. 6
Sodium metal crystallises in body centred cubic lattice with cell edge 427 pm. Thus, radius of sodium atom is
1. 429 pm
2. 214.5 pm
3. 186 pm
4. 185 pm
Total volume of atoms present in a face centred cubic unit cell of a metal ( r is atomic radius )
1. $\frac{20}{3} π r^{3}$
2. $\frac{24}{3} π r^{3}$
3. $\frac{12}{3} π r^{3}$
4. $\frac{16}{3} π r^{3}$
The edge of unit cell of FCC Xe crystal is 620 pm. The radius of Xe atom is
1. 219.25 pm
2. 235.16 pm
3. 189.37 pm
4. 209.87 pm
In a face-centred cubic lattice, atom X occupies the corners of the cube and atom Y occupies the face-centred positions. If one atom of Y is missing from one of the face-centred point, the formula of the compound is
1. $X_{2} Y$
2. $X_{2} Y_{5}$
3. $X_{2} Y_{2}$
4. $X Y_{2}$
A compound is formed by elements A and B. This crystallizes in the cubic structure when atoms A are the corners of the cube and atoms B are at the centre of the body. The simplest formula of the compound is
1. $A B_{4}$
2. $A B_{2}$
3. $A_{2} B$
4. $A B$
An ionic compound has a unit cell consisting of A ions at the corners of a cube and B ions on the centres of the faces of the cube. The empirical formula for this compound would be
1. $A B_{4}$
2. $A_{2} B$
3. $A B_{3}$
4. $A_{3} B$
Copper crystallises in fcc with a cell length of 361 pm. What is the radius of copper atom ?
1. 127.6 pm
2. 157 pm
3. 181 pm
4. 108 pm
Percentage of free space in cubic close packed structure and in body centred structure are respectively
1. 48% and 26%
2. 30% and 26%
3. 26% and 32%
4. 32% and 48%
A metal has bcc structure and the edge length of its unit cell is 3.04 A. The volume of the unit cell in $c m^{3}$ will be
1. $1.6 \times 10^{21} c m^{3}$
2. $2.81 \times 10^{- 23} c m^{3}$
3. $6.02 \times 10^{- 23} c m^{3}$
4. 32% and 48%
In face centred cubic unit cell edge length is
1. $\frac{4}{\sqrt{3}} r$
2. $\frac{4}{\sqrt{2}} r$
3. $2 r$
4. $\frac{\sqrt{3}}{2} r$
The edge length of a face centred cubic cell of an ionic substance is 508 pm. If the radius of the cation is 110 pm, the radius of the anion is
1. 144 pm
2. 288 pm
3. 398 pm
4. 618 pm
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. $12.08 \times 10^{23}$
The inter-ionic distance for cesium chloride crystal will be
1. $a$
2. $\frac{a}{2}$
3. $\frac{\sqrt{3} a}{2}$
4. $\frac{2 a}{\sqrt{3}}$
Sodium metal crystallizes as a body centred cubic lattice with the cell edge 4.29 A. What is the radius of sodium atom ?
1. $1.857 \times 10^{- 8} c m$
2. $2.371 \times 10^{- 7} c m$
3. $3.871 \times 10^{- 8} c m$
4. $9.312 \times 10^{- 7} c m$
Lithum forms body centred cube structure. The length of the side of its unit cell is 351 pm. Atomic radius of the lithium will be
1. 300 pm
2. 240 pm
3. 152 pm
4. 75 pm
In a face centred lattice of X and Y, X atoms are present at the corners while Y atoms are at face centers. Then the formula of the compound is
1. $X Y_{3}$
2. $X_{2} Y_{3}$
3. $X_{3} Y$
4. $X Y$
The fraction of total volume occupied by atoms in a simple cube is
1. $\frac{π}{2}$
2. $\frac{\sqrt{3} π}{8}$
3. $\frac{\sqrt{2} π}{6}$
4. $\frac{π}{6}$
Silver metal crystallises in a cubic closed packed arrangement with edge length 404 pm. Thus, radius of the silver atom is
1. 203.5 pm
2. 142.8 pm
3. 142.8 pm
4. 407.0 pm
Xenon crystallises in a face-centered cubic lattice and the edge of the unit cell is 620 pm. The radius of a xenon atom is
1. 438.5 pm
2. 219.20 pm
3. 536.94 pm
4. 265.5 pm
The length of the unit cell edge of a bcc lattice metal is 350 pm. Thus, volume of atoms in one mole of the metal is
1. $9.21 c m^{3}$
2. $7.25 c m^{3}$
3. $1.21 c m^{3}$
4. $4.00 c m^{3}$
A solid has a structure in which X-atoms are located at the cube corners of the unit cell, O-atoms are located at the cube edges and the Na-atoms at the cube centres. Lattice is of the type with formula
1. simple cubic, $N a_{2} X O_{3}$
2. tetrahedral, $N a X O_{3}$
3. body-centred, $N a X O_{3}$
4. simple-cubic, $N a X O_{3}$
If 'a' stands for the edge length of the cubic systems; simple cubic, body-centred cubic and face centred cubic, then the ratio of radii of the spheres in these system will be respectively
1. $\frac{1}{2} a : \frac{\sqrt{3}}{2} : \frac{\sqrt{2}}{2} a$
2. $1 a : \sqrt{3} a : \sqrt{2} a$
3. $\frac{1}{2} a : \frac{\sqrt{3}}{4} a : \frac{1}{2 \sqrt{2}} a$
4. $\frac{1}{2} a : \sqrt{3} a : \frac{1}{\sqrt{2}} a$
In a face centred cubic cell, an atom at the face contributes to the unit cell
1. $\frac{1}{2}$ part.
2. $\frac{1}{8}$ part.
3. 1 part
4. $\frac{1}{4}$ part.
The number of atoms / molecules contained in one body centered cubic unit cell is
1. 1
2. 6
3. 4
4. 2
Potassium crystallizes with a
1. Face-centred cubic lattice
2. Body-centred cubic lattice
3. Simple cubic lattice
4. Orthorhombic lattice
The packing fraction of the element that crystallizes in simple cubic arrangement is
1. $\frac{π}{4}$
2. $\frac{π}{6}$
3. $\frac{π}{3}$
4. $\frac{π}{2}$
Potassium crystallizes in a bcc lattice, hence the co-ordination number of potassium in potassium metal is
1. 0
2. 4
3. 6
4. 8
Which one of the following schemes of ordering closed packed sheets of equal sized spheres does not generate close packed lattice ?
1. ABCABC
2. ABACABAC
3. ABBAABBA
4. ABCBCABCBC
In a compound, atoms of element Y form ccp lattice and those of element X occupy 2/3rd of tetrahedral voids. The formula of the compound will be
1. $X_{3} Y_{4}$
2. $X_{4} Y_{3}$
3. $X_{2} Y_{3}$
4. $X_{2} Y$
A binary solid $(A^{+} B^{-})$ has a zinc blende structure with $B^{-}$ ions constituting the lattice and $A^{+}$ occupying 25% of the tetrahedral holes. The formula of the solid is
1. $A B$
2. $A_{2} B$
3. $A B_{2}$
4. $A B_{4}$
In the crystal lattice of diamond, carbon atoms adopt
1. fcc arrangement along with occupancy of 50% tetrahedral holes
2. fcc arrangement along with occupancy of 25% tetrahedral holes
3. fcc arangement along with occupancy of 25% octahedral hole
4. bcc arrangement
If 'Z' is the number of atoms in the unit cell that represents the closest packing sequence ---A B C A B---, the number of tetrahedral voids in the unit cell is equal to
1. Z
2. 2Z
3. $\frac{Z}{2}$
4. $\frac{Z}{4}$
In a multi-layered close-packed structure
1. there are twice as many tetrahedral holes as there are close-packed atoms
2. there are as many tetrahedral holes as there are close-packed atoms
3. there are twice as many octahedral holes as there are close-packed atoms
4. there are many tetrahedral holes as there are octahedral holes
The number of octahedral and tetrahedral sites in a cubical close packed array of N spheres respectively is
1. N and 2N
2. $\frac{N}{2}$ and N
3. 2N and N
4. 4N and 2N
In a metal oxide, the oxide ions are arranged in hexagonal close packing and metal ions occpy two-third of the octahedral voids. The formula of the oxide is
1. $M O$
2. $M_{2} O_{3}$
3. $M O_{2}$
4. $M_{2} O$
If 'Z' is the number of atoms in he unit cell that represents the closest packing sequence ---- A B C A B C ----, the number of tetrahedral voids in the unit cell is equal to
1. $2 Z$
2. $Z$
3. $\frac{Z}{2}$
4. $\frac{Z}{4}$
Co-ordination numbers in a square close packed structure and hexagonal close packed structure respectively, are
1. 6, 4
2. 2, 6
3. 3, 6
4. 4, 6
The arrangement ABC ABC ABC ........ is referred as
1. Cubic close packing
2. Hexagonal close packing
3. Tetragonal close packing
4. Octahedral close packing
In a CCP lattice of X and Y, X atoms are present at the corners like Y atoms are at face centres. Then the formula of the compound would be if one of the X atoms from a corner is replaced by Z atoms (also monovalent) ?
1. $X_{7} Y_{24} Z_{2}$
2. $X_{7} Y_{24} Z$
3. $X_{24} Y_{7} Z$
4. $X Y_{24} Z$
The maximum radius of sphere that can be fitted in the octahedral hole of cubical closed packing of sphere of radius r is
1. 0.732r
2. 0.414r
3. 0.225r
4. 0.155r
The number of octahedral sites per sphere in a fcc structure is
1. 1
2. 4
3. 2
4. 8
For an ionic solid of the general formula AB and co-ordination number 6, the value of the radius ratio will be
1. less than 0.225
2. in between 0.225 and 0.414
3. between 0.414 and 0.732
4. greater than 0.732
The ratio of cationic radius to anionic radius in an ionic crystal is greater than 0.732. Its co-ordination number is
1. 6
2. 1
3. 8
4. 4
In orthorhombic, the value of a, b and c are respectively 4.2 A, 8.6 A, 8.3 A. Given the molecular mass of the solute is $155 g m m o l^{- 1}$ and that of density is 3.3 gm/cc, hte number of formula units per unit cell is
1. 2
2. 3
3. 4
4. 6
The structure of TICl is similar to CsCl. What would be the radius ratio in TICl
1. 0.155 - 0.225
2. 0.225 - 0.414
3. 0.414 - 0.732
4. 0.732 - 1.000
In which of the following crystals alternate tetrahedral voids are occupied ?
1. NaCl
2. ZnS
3. $C a F_{2}$
4. $N a_{2} O$
Which of the following contains rock salt structure ?
1. $S r F_{2}$
2. $M g O$
3. $A l_{2} O_{3}$
4. All
Structure similar to zinc blende is found in
1. AgCl
2. NaCl
3. CuCl
4. TICl
In CsCl lattice the co-ordination number of $C s^{+}$ ion is
1. 2
2. 8
3. 4
4. 12
Potassium fluoride has NaCl type structure. What is the distance between $K^{+}$ and $F^{-}$ ions if cell edge is a cm ?
1. 2a cm
2. $\frac{a}{2} c m$
3. 4a cm
4. $\frac{a}{4} c m$
In NaCl lattice the co-ordination number of $C l^{-}$ ion is
1. 2
2. 6
3. 4
4. 8
A sodium is made of two elements X and Z. The atoms Z are in CCP arrangement while the atoms X occupy all the tetraheral sites. What is the formula of the compound ?
1. $X Z$
2. $X Z_{2}$
3. $X_{2} Z$
4. $X_{2} Z_{3}$
How many unit cells are present in a cube shaped ideal crystal of NaCl of mass 1.00 g ?
1. $2.57 \times 10^{21}$
2. $5.14 \times 10^{21}$
3. $1.28 \times 10^{21}$
4. $1.71 \times 10^{21}$
Select the correct statement (s)
a) The C.N. of cation occupying a tetrahedral hole is 4.
b) The C.N. of cation occupying an octahedral hole is 6.
c) In Schottky defects, the density of the lattice decreases.
1. a, b
2. b, c
3. a, b, c
4. a, c
A mineral having the formula $X Y_{2}$ crystallises in the cubic closest-packed lattice with the A-atoms occupying the lattice point. Fraction of the tetrahedral sites ocupied by B-atoms is
1. 1.00
2. 0.52
3. 0.68
4. 0.74
CsBr has bcc structure with edge length 4.3 pm. The shortest interionic distance between $C s^{+}$ and $B r^{-}$ is
1. 3.72 A
2. 1.86 A
3. 7.44 A
4. 4.3 A
Experimentally it was found that a metal oxide has formula $M_{0.98} O_{1}$ . Metal M is present as $M^{2 +}$ and $M^{3 +}$ in its fraction of the metal which exists as $M^{3 +}$ would be
1. 6.05%
2. 5.08%
3. 7.01%
4. 4.08%
CsCl crystallises in body centred cubic lattice. If 'a' is its edge length, then which of the following expressions is correct ?
1. $r_{c s +} + r_{c l -} = \frac{a \sqrt{3}}{2}$
2. $r_{c s +} + r_{c l -} = a \sqrt{3}$
3. $r_{c s +} + r_{c l -} = - 3 a$
4. $r_{c s +} + r_{c l -} = \frac{3 a}{2}$
The number of atoms in 100 g of an fcc crystal with density $d = \frac{10 g}{c m^{3}}$ and cell edge equal to 100 pm is
1. $4 \times 10^{25}$
2. $3 \times 10^{25}$
3. $2 \times 10^{25}$
4. $1 \times 10^{25}$
What is the formula of a magnetic oxide of cobalt used in recording tapes that crystallises with cobalt atoms occupying one-eighth of the tetrahedral holes and one-half of the octahedral holes in a closest packed array of oxide ions ?
1. $C o_{2} O_{3}$
2. $C o O_{2}$
3. $C o_{3} O_{4}$
4. $C o O$
The co-ordination number of a metal crystallizing in a hexagonal close packed (hcp) structure is
1. 6
2. 8
3. 4
4. 12
In the calcium fluoride structure the co-ordination number of the cation and anions are respectively
1. 6, 6
2. 4, 4
3. 8, 4
4. 4, 8
The number of unit cells in 58.5 g of NaCl is nearrly
1. $6 \times 10^{20}$
2. $3 \times 10^{22}$
3. $1.5 \times 10^{23}$
4. $0.5 \times 10^{24}$
In which of the following crystals alternate tetrahedral voids are occupied ?
1. NaCl
2. ZnS
3. $C a F_{2}$
4. $N a_{2} O$
Radii of $A^{+}$ and that of $X^{-}$ and $X^{-}$ have been given as
$A^{+}$ = 1.00 pm
$X^{-}$ = 1.00 pm
$Y^{-}$ = 2.00 pm
Thus, ratio of volume of AX and AY unit cells is
1. 17.54
2. 0.057
3. 1.0
4. 0.217
The radius of the $N a^{+}$ is 95 pm and that of $C l^{-}$ ion is 181 pm. Predict the co-ordination number of $N a^{+}$
1. 4
2. 6
3. 8
4. unpredictable
Experimenttally, it was found that a metal oxide has formula $M_{0.95} O$ . Metal M is present as $M^{2 +}$ and $M^{3 +}$ in its oxide. Fraction of the metal which exists as $M^{3 +}$ would be
1. 10.52%
2. 4.08%
3. 6.05%
4. 5.08%
How many unit cells are present in a cube-shaped ideal crystal of NaCl of mass 1.00 g [Atomic masses : Na = 23, Cl = 35.5] ?
1. $2.57 \times 10^{21}$ unit cells
2. $5.14 \times 10^{21}$ unit cells
3. $1.28 \times 10^{21}$ unit cells
4. $1.71 \times 10^{21}$ unit cells
The radius of $A g^{+}$ ion is 126 pm and that of $I^{-}$ ion is 216 pm. The co-ordination number of $A g^{+}$ is
1. 2
2. 4
3. 6
4. 8
The tetrahedral voids formed in ccp arrangement of $C l^{-}$ ions in rock salt structure are
1. Occupied by $N a^{+}$ ions.
2. Occupied by $C l^{-}$ ions.
3. Occupied by either $N a^{+}$ or $C l^{-}$ ions
4. Vacant
In a closed packed structure of mixed oxides, it is found that lattice has $O^{2 -}$ (oxide ion) and one-half of octahedral voids are occupied by trivalent cations $(A l^{3 +})$ and one-eighth of tetrahedral voids are occupied by divalent cations $(B^{2 +})$ . This, mixed oxide is
1. $A_{2} B O_{3}$
2. $A_{2} B O_{4}$
3. $A B_{2} O_{4}$
4. $A B O_{3}$
An element X (At. wt. = 80 g/mol) having fcc structure, calculate the number of unit cells in 8 g of X
1. $0.4 \times N_{A}$
2. $0.1 \times N_{A}$
3. $4 \times N_{A}$
4. $\frac{N_{A}}{40}$
In which of the following compound, 8:8 co-ordination is found
1. CsCl
2. MgO
3. $A l_{2} O_{3}$
4. All of these
For some crystals, the radius ratio for cation and anion is 0.525, its co-ordination number will be
1. 2
2. 6
3. 4
4. 8
In solid oxide ions are arranged in ccp. One-sixth of tetralhedral voids are occupied by cation A while one-third of octahedral voids are occupied by cation B. What is the formula of compound ?
1. $A B_{2} O$
2. $A B O_{3}$
3. $A_{2} B_{3} O$
4. $A_{3} B_{2} O$
Which of the following expressions is correct in the case of a sodium chloride unit cell (edge length = a) ?
1. $r_{c} + r_{a} = \frac{a}{2}$
2. $r_{c} + r_{a} = a$
3. $r_{c} + r_{a} = 2 a$
4. $r_{c} + r_{a} = 2^{1 / 2} a$
An element (atomic mass = $100 \frac{g}{m o l}$ ) having bcc structure has unit cell edge 400 pm. The ensity of the element is
1. $10.736 \frac{g}{c m^{3}}$
2. $2.144 \frac{g}{c m^{3}}$
3. $7.289 \frac{g}{c m^{3}}$
4. $5.188 \frac{g}{c m^{3}}$
MgO exists in a rock-salt type unit cell. Each $M g^{+ 2}$ ion will be in contact with
1. $4 O^{- 2}$ ions.
2. $6 O^{- 2}$ ions.
3. $8 O^{- 2}$ ions
4. $2 O^{- 2}$ ions.
An $A B_{2}$ type structure is found in
1. NaCl
2. $C a F_{2}$
3. $A l_{2} O_{3}$
4. $N_{2} O$
Cesium (chloride) on heating to 760 K changes into
1. CsCl(g)
2. NaCl structure
3. antifluorrite structure
4. ZnS structure
The ionic radii of $R b^{+}$ and $I^{-}$ are 1.46 and 2.16 A. The most probable type of structure exhibited it is
1. CsCl type
2. NaCl type
3. ZnS type
4. $C a F_{2}$ type.
A group IV A element with a density of $11.35 \frac{g}{c m^{3}}$ crystallises in a face centered cubic lattice whose unit cell edge length is 4.95 A. Calculate its atomic mass.
1. $207.2 \frac{g}{m o l}$
2. $180 \frac{g}{m o l}$
3. $109.9 \frac{g}{m o l}$
4. $208.8 \frac{g}{m o l}$
Select the incorrect statement for CsCl crystal
1. Co-ordination No. for $C s^{+}$ and $C l^{-}$ is 6.
2. $\frac{r_{c s^{+}}}{r_{c l^{-}}} = 0.732$
3. The structure changes to NaCl at 760 K
4. $C l^{-}$ ions are present at cubic sites.
For cubic co-ordination the value of radius ratio is
1. 0.414 - 0.732
2. 0.225 - 0.414
3. 0.000 - 0.225
4. 0.732 - 1.000
The unit cell of a NaCl lattice
1. Is body centred cube
2. Has $3 N a^{+}$ ions
3. Is electrically changed
4. Has 4 NaCl units
How many molecules are there in the unit cell of sodium chloride ?
1. 2
2. 6
3. 4
4. 8
The number of atoms in 100 g of an fcc crystal with density d = $10 \frac{g}{c m^{3}}$ and cell edges as 200 pm is equal to
1. $3 \times 10^{25}$
2. $5 \times 10^{24}$
3. $1 \times 10^{25}$
4. $5.96 \times 10^{- 3}$
Structure of ZnS is
1. Body centred cubic
2. Simple cubic
3. Face centred cubic
4. Fluorite structure
The inter-metallic compound LiAg crystallizes in cubic lattice in which both lithium and silver have co-ordination number of eight. The crystal class is
1. Simple cube
2. Face-centred cube
3. Body-centred cube
4. None of these
For an ionic crystal of the type AB, the value of (limiting) radius ratio is 0.40. The value suggest that the crystal structure should be
1. Octahedral
2. Tetrahedral
3. Square planar
4. Plane triangle
Potassium has a bcc structure with nearest neighbour distance 4.52 A. Its atomic weight is 39. Its density $(i n k g m^{- 3})$ will be
1. 454
2. 804
3. 852
4. 908
In which of the following substances the carbon atom is arranged in a regular tetrahedral structure ?
1. Diamond
2. Benzene
3. Graphite
4. Carbon black
If the value of ionic radius ratio $(\frac{r_{c}}{r_{a}})$ is 0.52 in an ionic compound, the geometrical arrangement of ions in crystal is
1. Tetrahedral
2. Planar
3. Octahedral
4. Pyramidal
In the closest packed structure of a metallic lattice, the number of nearest neighbours of a metallic atom is
1. Six
2. Four
3. Eight
4. Twelve
If the radius ratio is in the ranger of 0.414 - 0.732, then the co-ordination number will be
1. 2
2. 6
3. 4
4. 8
The formula for determination of density of unit cell is
1. $\frac{a^{3} \times N_{0}}{N \times M} g c m^{- 3}$
2. $\frac{a^{3} \times M}{N \times N_{0}} g c m^{- 3}$
3. $\frac{N \times M}{a^{3} \times N_{0}} g c m^{- 3}$
4. $\frac{M \times N}{a^{3} \times N} g c m^{- 3}$
It the distance between $N a^{+}$ and $C l^{-}$ ions in sodium chloride crystal is X pm, the length of the edge of the unit cell is
1. 4X pm
2. $\frac{X}{4} p m$
3. $\frac{X}{2} p m$
4. 2X pm
In $A^{+} B^{-}$ ionic compound, radii of $A^{+}$ and $B^{-}$ ions are 180 pm and 187 pm respectively. The crystal structure of this compound will be
1. NaCl type
2. CsCl type
3. ZnS type
4. Similar to diamond
An example of a non-stoichiometric compound is
1. $A l_{2} O_{3}$
2. $N i O_{2}$
3. $F e_{3} O_{4}$
4. PbO
For an ionic crystal of the general formula AX and co-ordination number 6, the value of radius ratio will be
1. Greater than 0.73
2. In between 0.41 and 0.22
3. In between 0.73 and 0.41
4. Less than 0.22
In orthorhombic, the value of a, b, c are respectively 4.2 A, 8.6 A, and 8.3 A. The molecular mass of the solute is $155 g m m o l^{- 1}$ and that of density is $3.3 \frac{g m}{c c}$ , the number of formula units per unit cell is
1. 2
2. 3
3. 4
4. 6
In a solid 'AB' having the NaCl structure, 'A' atoms occupy the corners of the cubic unit cell. If all the face-centred atoms along one of the axes are removed, then the resultant stiochiometry of the solid is
1. $A B_{2}$
2. $A_{2} B$
3. $A_{4} B_{3}$
4. $A_{3} B_{4}$
Ferrous oxide has a cubic structure and each edge of the unit cell is 5.0 A. Assuming density of the oxide as $4.0 \frac{g}{c m^{3}}$ , then the number of $F e^{2 +}$ and $O^{2 -}$ ions present in each unit cell will be
1. Four $F e^{2 +}$ and two $O^{2 -}$
2. Two $F e^{2 +}$ and Four $O^{2 -}$
3. Four $F e^{2 +}$ and Four $O^{2 -}$
4. Three $F e^{2 +}$ and Three $O^{2 -}$
In the Zinc blende structure (ZnS), $S^{2 -}$ adopts ccp arrangement and $Z n^{2 +}$ occupies
1. Octahedral sites
2. Hexagonal sites
3. Tetrahedral sites
4. Both Octahedral and Tetrahedral sites
A metal crystalli8zes in two cubic phases, face centred cubic (fcc) and body centred cubic (bcc) whose unit cell length are 3.5 and 3.0 A respectively. Calculate the ratio of density of fcc and bcc.
1. 2.123
2. 1.259
3. 5.124
4. 3.134
NiO adopts a rock salt structure., The co-ordination number of the $N i^{2 +}$ ion is
1. Two
2. Four
3. Twelve
4. Six
The co-ordination of a metal crystallizing in a hexagonal close packed structure is
1. 4
2. 6
3. 8
4. 12
Lithium Selenide can be described as a closest-packed array of selenide ions with lithium ions in all of the tetrahedral holes. Formula of lithium seleneide is
1. $L i_{2} S e$
2. $L i S e$
3. $L i S e_{2}$
4. $L i_{3} S e$
In the crystal of CsCl, the nearest neighbours of each Cs ion are
1. Six Chloride ions
2. Six Cs ions
3. Eight chloride ions
4. Eight Cs ions
Space lattice of $C a F_{2}$ is
1. Face centred cubic
2. Body centred cubic
3. Simple cubic
4. Hexagonal closed packing
How many chloride ions are there around sodium ion in sodium chloride crystal ?
1. 6
2. 8
3. 4
4. 3
A binary solid $(A^{+} B^{-})$ has a rock salt structure. If the edge length is 400 pm and radius cation is 75 pm , the radius of anion is
1. 100 pm
2. 125 pm
3. 250 pm
4. 325 pm
What fraction of the surface of a cstal of Cd at T = 298 K consists of vacncies ?
$∆_{s u b} H^{o} (C d) = 113.02 k J m o l^{- 1}$ . Energy needed to form a vacancy is approximately 60% of $∆_{s u b} H^{o}$ .
1. $1.50 \times 10^{10}$
2. $6.02 \times 10^{- 23}$
3. $6.02 \times 10^{22}$
4. $1.30 \times 10^{- 12}$
The correct statement regarding defects in solids is
1. Frenkel defect is favoured by a very small difference in the size of cation and anion
2. Frenkel defect is not a dislocation defect
3. Trapping of $e^{-}$ in lattice leads to the formation of F-center
4. Schottky defects have no effect on the physical properties of solid
In AgBr crystal, the ion size lies in the order $A g^{+}$ << $B r^{-}$ . The AgBr crystal should have the following characteristics
1. Deficiencies (perfect) crystal
2. Schottky defect only
3. Frenkel defect only
4. Both Schottky and Frenkel defects
Frenkel defect is caused due to
1. An ion missing from the normal lattice site creating a vacancy
2. An extra positive ion occupying an interstitial position in the lattice
3. An extra negative ion occupying an interstitial position in the lattice
4. The shift of a positive ion from its normal lattice site to an interstitial site.
How many energy levels are present in 3s conduction band of a single crystal of sodium weighing 25.6 mg ?
1. $7.01 \times 10^{20}$
2. $7.01 \times 10^{23}$
3. $6.02 \times 10^{23}$
4. $6.68 \times 10^{20}$
Which defect causes decrease in the density of crystal ?
1. Frenkel
2. Interstitial
3. Schottky
4. F-Centre
To get a n-type semi-conductor, the impurity to be added to silicon should have which of the following number of valence electrons
1. 1
2. 2
3. 3
4. 5
The flame colours of metal ions are due to
1. Metal excess defect
2. Schottky defect
3. Metal deficiency defect
4. Frenkel defect
Schottky defect in crystals is observed when
1. Density of crystal is increased
2. Unequal number of cations and anions are missing from the lattice
3. An ion leaves its normal sites and occupies an interstitial site
4. Equal number of cations and anions are missing from the lattice
When electrons are trapped into the crystal in anion vacancy, the defect is known as
1. F-centres
2. Frenkel defect
3. Stoichiometric defect
4. Schottky defect
In which of the following oxides conducting or insulating property of oxide is dependent on temperature
1. $S i O_{2}$
2. $T i O$
3. $M g O$
4. $T i_{2} O_{3}$
The correct statement in the following is
1. The ionic crystal of AgBr has Schottky defect
2. The unit cell having crystal parameters , $a = b \neq c,$ $α = β = 90 °, γ = 120 °$ is hexagonal
3. In ionic compounds having Frenkel defect the ratio $\frac{γ_{+}}{γ_{-}}$ is high
4. The co-ordination number of $N a^{+}$ ion in NaCl is 4.
The pycnometric density of sodium chloride crystal is $2.165 \times 10^{3} k g m^{- 3}$ while its X-rays density is $2.178 \times 10^{3} k g m^{- 3}$ . The fraction of unoccupied sites in sodium chloride crystal is
1. $5.96 \times 10^{- 1}$
2. $5.96$
3. $5.96 \times 10^{- 2}$
4. $5.96 \times 10^{- 3}$
In the laboratory, sodium chloride is made by burning the sodium in the atmosphere of chlorine which is yellow in colour. The cause of yellow colour is
1. Presence of $N a^{+}$ ions in the crystal lattice
2. Presence of $C l^{-}$ ions in the crystal lattice
3. Presence of electron in the crystal lattice
4. Presence of face centred cubic crystal lattice
If NaCl is doped with $10^{- 3}$ mole % of $S r C l_{2}$ , then number of cationic vacancies is
1. $6.02 \times 10^{- 18} m o l^{- 1}$
2. $10^{- 5} m o l^{- 1}$
3. $6.02 \times 10^{20} m o l^{- 1}$
4. $6.02 \times 10^{18} m o l^{- 1}$
The following is not a function of an impurity present in a crystal
1. Contributing to scattering
2. Having tendency to diffuse
3. Establishing thermal equilibrium
4. Introducing new electronic energy levels
The correct statement regarding F-centre is
1. Electrons are held in the voids of crystals
2. F-centre produces colour to the crystals
3. Conductivity of the crystal increases due to F-centre
4. All
If a non-metal is added to the interstitial sites of a metal, then the metal becomes
1. More ductile
2. Less tensile
3. Less malleable
4. Softer
NaCl shows Schottky defects and AgCl Frenkel defects. Their electrical conductivity is due to
1. motion of ions and not the motion of electrons
2. motion of electrons and not the motion of ions
3. Lower co-ordination number of NaCl
4. Higher co-ordination number of AgCl
Bragg's X-ray diffraction studies are successful when
1. $λ > 2 d$
2. $λ \leq 2 d$
3. $λ \geq 2 d$
4. $λ = 2 d$
Which of the following relation is correct for first-order Bragg's diffraction ?
1. $\sin \emptyset = \frac{2 a}{λ} (h^{2} + k^{2} + l^{2})$
2. $\sin \emptyset = \frac{2 a}{λ} {(h^{2} + k^{2} + l^{2})}^{1 / 2}$
3. $\sin \emptyset = \frac{λ}{2 a} (h^{2} + k^{2} + l^{2})^{1 / 2}$
4. $\sin \emptyset = \frac{λ}{2 a} (h^{2} + k^{2} + l^{2})^{2}$
The oxide which shows metallic conduction is
1. $R e O_{3}$
2. VO
3. $C r O_{2}$
4. All of these
Which one of the following metal oxides is anti-ferromagnetic in nature ?
1. $M n O_{2}$
2. $T i O_{2}$
3. $V O_{2}$
4. $C r O_{2}$
Certain crystals produce electric signals on application of pressure. This phenomenon is called
1. Pyroelectricity
2. Ferroelectricity
3. Piezoelectricity
4. Ferrielectricity
Which of the following pairs contain ferromagnetic and ferrimagnetic solids respectively ?
1. $F e_{2} O_{3}, F e_{3} O_{4}$
2. $F e_{3} O_{4}, C r_{2} O_{3}$
3. $C r O_{2}, F e_{3} O_{4}$
4. $C r_{2} O_{3}, C r O_{2}$
Which of the following statements are true ?
1. Piezoelectricity is due to net dipole moment
2. Ferroelectricity is due to alignment of dipoles in same direction
3. Pyroelectricity is due to heating polar crystals
4. All of the above.
The diffraction of barium with X-radiation of wavelength 227 pm gives a first-order diffraction at $30 °$ . Thus, distance between the two planes is
1. 114.5 pm
2. 229 pm
3. 458 pm
4. 227 pm
Which arrangement of electron decides ferrimagnetism ?
1. $↓ ↓ ↓ ↓ ↓$
2. $↓ ↑ ↓ ↑$
3. $↓ ↓ ↑ ↓ ↓$
4. None of these
In Bragg'sd X-ray diffraction studies, 100 pm X-ray has second-order diffration at glancing angle of $30 °$ . Its interplanar spacing will be
1. 200 pm
2. 150 pmm
3. 100 pm
4. 144 pm
At what angles for the first-order diffraction, spacing between two planes respectivelyh is $λ$ and $\frac{λ}{2}$ ?
1. $0 °, 90 °$
2. $90 °, 0 °$
3. $30 °, 90 °$
4. $90 °, 30 °$
Which substance shows anti-ferro-magnetism ?
1. $Z n O_{2}$
2. $C d O$
3. $C r O_{2}$
4. $M n O_{3}$
ASSERTION : In Frenkel defect in an ionic crystal, an ion is displaced from its normal site to an interstitial site.
REASON : There is both a vacancy and an interstitional ion.
1. If both assertion and reason are true and the reason is the correct explanation of the assertion
2. If both assertion and reason are true but the reason is not the correct explanation of the assertion
3. If assertion is true but reason is false.
4. If assertion is false but reason is true.
ASSERTION : If the length of the unit cell of LiCl having NaCl structure is 5.14 A, the ionic radius of $C l^{-}$ ion is 1.82 A.
REASON : Anion-anion contact is retained in LiCl structure because anions constitute the lattice.
1. If both assertion and reason are true and the reason is the correct explanation of the assertion
2. If both assertion and reason are true but the reason is not the correct explanation of the assertion
3. If assertion is true but reason is false.
4. If assertion is false but reason is true.
ASSERTION : The close packing of atoms in cubic structure is in the order $f c c > b c c > s c$ .
REASON : Packing density = $\frac{V o l u m e o f u n i t c e l l}{a^{3}}$
1. If both assertion and reason are true and the reason is the correct explanation of the assertion
2. If both assertion and reason are true but the reason is not the correct explanation of the assertion
3. If assertion is true but reason is false.
4. If assertion is false but reason is true.
ASSERTION : In point defect density of solid may decrease and increase
REASON : Formation $F e_{0.93} O$ is called non-stoichiometric defects
1. If both assertion and reason are true and the reason is the correct explanation of the assertion
2. If both assertion and reason are true but the reason is not the correct explanation of the assertion
3. If assertion is true but reason is false.
4. If assertion is false but reason is true.
ASSERTION : In hexagonal close packing vacant spaces are between three touching spheres whose centres lie at the corners of an equilateral triangle.
REASON : In hexagonal close packing voids are called square voids
1. If both assertion and reason are true and the reason is the correct explanation of the assertion
2. If both assertion and reason are true but the reason is not the correct explanation of the assertion
3. If assertion is true but reason is false.
4. If assertion is false but reason is true.
ASSERTION : Anti-ferro-magnetic substances on heating to high temperature become para-magnetic.
REASON : On heating, randomisation of spins occurs.
1. If both assertion and reason are true and the reason is the correct explanation of the assertion
2. If both assertion and reason are true but the reason is not the correct explanation of the assertion
3. If assertion is true but reason is false.
4. If assertion is false but reason is true.
ASSETION : Stoichiometric compounds obey the law of constant compostion.
REASON : Schottky and Frenkel defects are observed in stoichiometric compounds
1. If both assertion and reason are true and the reason is the correct explanation of the assertion
2. If both assertion and reason are true but the reason is not the correct explanation of the assertion
3. If assertion is true but reason is false.
4. If assertion is false but reason is true.
ASSERTION : Bragg's equation has no solution, if n = 2 and $λ > d .$ .
REASON : Bragg's equation is $n λ = 2 d \sin \emptyset$
1. If both assertion and reason are true and the reason is the correct explanation of the assertion
2. If both assertion and reason are true but the reason is not the correct explanation of the assertion
3. If assertion is true but reason is false.
4. If assertion is false but reason is true.
ASSERTION : $N a_{2} O$ adopts structure similar to that of $C a F_{2}$ but positions of positive and negative ions are reversed.
REASON : The structure of $N a_{2} O$ is also called spinal structure.
1. If both assertion and reason are true and the reason is the correct explanation of the assertion
2. If both assertion and reason are true but the reason is not the correct explanation of the assertion
3. If assertion is true but reason is false.
4. If assertion is false but reason is true.
ASSERTION : Solids having more F-centres possess intense colours.
REASON : Excess of $N a^{+}$ in NaCl solid having F-centres makes it appear pink.
1. If both assertion and reason are true and the reason is the correct explanation of the assertion
2. If both assertion and reason are true but the reason is not the correct explanation of the assertion
3. If assertion is true but reason is false.
4. If assertion is false but reason is true.
ASSERTION : Triclinic system is the most unsymmetrical system.
REASON : No axial angle is equal to $90 °$ in triclinic system
1. If both assertion and reason are true and the reason is the correct explanation of the assertion
2. If both assertion and reason are true but the reason is not the correct explanation of the assertion
3. If assertion is true but reason is false.
4. If assertion is false but reason is true.
ASSERTION : Frenkel defects are sbhown by silver halides.
REASON : $A g^{+}$ ions have small size.
1. If both assertion and reason are true and the reason is the correct explanation of the assertion
2. If both assertion and reason are true but the reason is not the correct explanation of the assertion
3. If assertion is true but reason is false.
4. If assertion is false but reason is true.
ASSERTION : In AgCl crystal, Frenkel defects can be observed.
REASON : $A g^{+}$ is a small sized cation.
1. If both assertion and reason are true and the reason is the correct explanation of the assertion
2. If both assertion and reason are true but the reason is not the correct explanation of the assertion
3. If assertion is true but reason is false.
4. If assertion is false but reason is true.
ASSERTION : A crystal having fcc structure is more closely packed than a crystal having bcc structure.
REASON : Packing fraction for fcc structure is double than that of bcc structure.
1. If both assertion and reason are true and the reason is the correct explanation of the assertion
2. If both assertion and reason are true but the reason is not the correct explanation of the assertion
3. If assertion is true but reason is false.
4. If assertion is false but reason is true.
ASSERTION : ZnO becomes yellow when it is heated.
REASON : NaCl becomes yellow when heated in the presence of Na vapours due to anion vacancy.
1. If both assertion and reason are true and the reason is the correct explanation of the assertion
2. If both assertion and reason are true but the reason is not the correct explanation of the assertion
3. If assertion is true but reason is false.
4. If assertion is false but reason is true.
ASSERTION : Covalent crystals have the higher melting points.
REASON : Covalent bonds are stronger than ionic bonds.
1. If both assertion and reason are true and the reason is the correct explanation of the assertion
2. If both assertion and reason are true but the reason is not the correct explanation of the assertion
3. If assertion is true but reason is false.
4. If assertion is false but reason is true.
ASSERTION : CsCl has body-centred cubic arrangement
REASON : CsCl has one $C s^{+}$ ion and 8 $C l^{-}$ ions in its unit cell.
1. If both assertion and reason are true and the reason is the correct explanation of the assertion
2. If both assertion and reason are true but the reason is not the correct explanation of the assertion
3. If assertion is true but reason is false.
4. If assertion is false but reason is true.
ASSERTION : In NaCl crystal each $N a^{+}$ ion is touching 6 $C l^{-}$ ions but these $C l^{-}$ ions do not touch each other.
REASON : The radius ratio is greater than 0.414 required for exact fitting
1. If both assertion and reason are true and the reason is the correct explanation of the assertion
2. If both assertion and reason are true but the reason is not the correct explanation of the assertion
3. If assertion is true but reason is false.
4. If assertion is false but reason is true.
ASSERTION : In NaCl crystal, all the octahedral voids are occupied by $N a^{+}$ ions.
REASON : The number of octahedral voids is equal to the number of $C l^{-}$ ions in the packing.
1. If both assertion and reason are true and the reason is the correct explanation of the assertion
2. If both assertion and reason are true but the reason is not the correct explanation of the assertion
3. If assertion is true but reason is false.
4. If assertion is false but reason is true.
ASSERTION : An important feature of Fluorite structures is that cations being large in size occupy FCC lattice points, whereas anions occupy all the tetraheral voids giving the formula unit : $A B_{2}$ (A : Cation ; B : Anion)
REASON : There are 6 cations and 12 anions per FCC unit cell of the fluorite structure.
1. If both assertion and reason are true and the reason is the correct explanation of the assertion
2. If both assertion and reason are true but the reason is not the correct explanation of the assertion
3. If assertion is true but reason is false.
4. If assertion is false but reason is true.
ASSERTION : The octahedral voids have double the size of the tetrahedral voids in a crystal.
REASON : The number of tetrahedral voids is double the number of octahedral voids in a crystal.
1. If both assertion and reason are true and the reason is the correct explanation of the assertion
2. If both assertion and reason are true but the reason is not the correct explanation of the assertion
3. If assertion is true but reason is false.
4. If assertion is false but reason is true.
The mass of unit cell of $C a F_{2}$ (fluorite structure) corresponds to
1. mass of 8 $C a^{+ +}$ ions and 4 $F^{-}$ ions
2. mass of 4 $C a^{+ +}$ ions and 8 $F^{-}$ ions
3. mass of 4 $C a^{+ +}$ ions and 4 $F^{-}$ ions
4. mass of 1 $C a^{+ +}$ ion and 2 $F^{-}$ ions
Close packing is maximum in the Crystal which is
1. Simple cube
2. bcc
3. fcc
4. None
An ionic compound AB has ZnS type of structure if the radius $A^{+}$ is 22.5 pm, then the ideal radius of $B^{-}$ is
1. 54.35 pm
2. 100 pm
3. 145.16 pm
4. None
A pure crystalline substance, on being heated gradually, first forms a turbid looking liquid and then the turbidity completely disappears. This behaviour is the characteristic of substances forming
1. Isomeric crystals
2. Liquid crystals
3. Isomorphous crystals
4. Allotropic crystals
Under which category iodine crystals are placed during the following
1. Ionic crystal
2. Metallic crystal
3. Molecular crystal
4. Covalent crystal
How many molecules are there in the unit cell of sodium chloride ?
1. 2
2. 4
3. 6
4. 8
The structure of TICl is similar to CsCl. What would be the radius ratio in TICl ?
1. 0155 - 0.225
2. 0.225 - 0.414
3. 0.414 - 0.732
4. 0.732 - 1.000
Na and Mg crystallize in BCC and FCC type crystals respectively, then the number of atoms of Na and Mg present in the unit cell of their respective crystal is
1. 4 and 2
2. 9 and 14
3. 14 and 9
4. 2 and 4
In the closest packed packed structure of ametallic lattice, the number of nearest neighbours of a metallic atom is
1. Twelve
2. Four
3. Eight
4. Six
The number of atoms in 100 g of an fcc crystal with densitty d = $10 \frac{g}{c m^{3}}$ and cell edge equal to 100 pm is equal to
1. $4 \times 10^{25}$
2. $3 \times 10^{25}$
3. $2 \times 10^{25}$
4. $1 \times 10^{25}$
Potassium has a bcc structure with nearest neighbour distance 4.52 A. Its atomic weight is 39. Its density $(i n k g m^{- 3})$ will be
1. 454
2. 804
3. 852
4. 910
Ferrous oxide has a cubic structure and each edge of the unit cell is 5.0 A. Assuming density of the oxide as $4.0 g - c m^{- 3}$ , then the number of $F e^{2 +}$ and $O^{2 -}$ ions present in each unit cell will be
1. Four $F e^{2 +}$ and four $O^{2 -}$
2. Two $F e^{2 +}$ and four $O^{2 -}$
3. Four $F e^{2 +}$ and two $O^{2 -}$
4. Three $F e^{2 +}$ and three $O^{2 -}$
In $A^{+} B^{-}$ ionic compound, radii of $A^{+}$ and $B^{-}$ ions are 180 pm and 187 pm respectively . The crystal structure of this compound will be
1. NaCl type
2. CsCl type
3. ZnS type
4. Similar to diamond
In the calcium fluoriode structure the co-ordination number of the cation and aniopns are respectively
1. 6, 6
2. 8, 4
3. 4, 4
4. 4, 8
Which one of the following has Frenkel defect ?
1. Sodium Chloride
2. Graphite
3. Silver Bromide
4. Diamond
Which of the following molecules has three-fold axis of symmetry ?
1. $N H_{3}$
2. $C_{2} H_{4}$
3. $C O_{2}$
4. $S O_{2}$
In a fcc arrangement of A and B atoms, where A atopms are at the corners of the unit cell, B atoms at the face centers, two atoms are missing from two corners in each unit cell, then the simplext formula of the compound is
1. $A_{7} B_{6}$
2. $A_{6} B_{7}$
3. $A_{7} B_{24}$
4. $A B_{4}$
In fluorite structure $(C a F_{2})$
1. $C a^{+ +}$ ions are ccp and $F^{-}$ ions are present in all the tetrahedral voids
2. $C a^{+ +}$ ions are ccp and $F^{-}$ ions are present in all the octrahedral voids
3. $C a^{+ +}$ ions are ccp and $F^{-}$ ions are present in all the octrahedral voids and half of ions are
4. None
Which one of the following is the most important statement ?
1. Brass is an interstitial alloy, while steel is a substantitutional alloy.
2. Brass is a substitutional alloy, while steel is an interstitial alloy
3. Brass and steel are both substitutional alloys
4. Brass and steel are both interstitial alloys
A solid is made of two elements P and Q. Atoms P are in ccp arrangement and atoms Q occupy all the octahedral voids and half of the tetrahedral voids, then the simplest formula of the compound is
1. $P Q_{2}$
2. $P_{2} Q$
3. $P Q$
4. $P_{2} Q_{2}$
Fraction of total volume occupied by atoms in a simple cube is
1. $\frac{π}{2}$
2. $\frac{\sqrt{3} π}{8}$
3. $\frac{\sqrt{2} π}{6}$
4. $\frac{π}{6}$
The limiting radius ratio of the complex ${[N i {(C N)}_{4}]}^{2 -}$ is
1. 0.225 - 0.414
2. 0.414 - 0.732
3. 0.155 - 0.225
4. None
If the ratio of co-ordination number P to that of Q be Y : Z, then the formula of the solid is
1. $P_{y} Q_{z}$
2. $P_{z} Q_{y}$
3. $P_{\frac{1}{y}} Q_{\frac{1}{z}}$
4. None
Xenon crystallizes in face centre cubic lattice and the edge of the unit cell is 6.20 pm, then the radius of xenon-atom is
1. 438.5 pm
2. 219.25 pm
3. 536.94 pm
4. 265.5 pm
The arrangement of $C l^{-}$ ions in CsCl structure is
1. hcp
2. fcc
3. bcc
4. Simple cubic
In closest packing of A type of atoms $(r a d i u s r_{A})$ , the radius of atom B that can be fitted into octahedral void is
1. $0.155 r_{A}$
2. $0.125 r_{A}$
3. $0.414 r_{A}$
4. $0.732 r_{A}$
The edge length of a cube is 400 pm. Its body diagonal would be
1. 600 pm
2. 566 pm
3. 693 pm
4. 500 pm
ASSERTION : Electrical conductivity of semi-conductors increases with increasing temperature
REASON : With increase in temperature, large number of electrons from the valence band can jump to the conduction band
1. If both assertion and reason are true and reason is the correct explanation of the assertion
2. If both assertion and reason are true and reason is not the correct explanation of the assertion
3. If assertion is true but reason is false
4. If assertion is false but reason is true.
ASSERTION : On heating ferro-magnetic or ferri-magnetic substances, they become para-magnetic
REASON : The electrons change their spin on heating
1. If both assertion and reason are true and reason is the correct explanation of the assertion
2. If both assertion and reason are true and reason is not the correct explanation of the assertion
3. If assertion is true but reason is false
4. If assertion is false but reason is true.