CBSE Class 12 Chemistry The Solid State MCQs Set E

Question: In CsCl type structure the coordination number of Cs⁺ and Cl⁻ are
a) 6,6
b) 6,8
c) 8,8
d) 8,6
Answer: a

Question: The radius ratio in CsCl is 0.93. The expected lattice structure is
a) tetrahedral
b) square planar
c) octahedral
d) body centred cubic
Answer: a

Question: The coordination number of Na⁺ in NaCl is
a) 6
b) 8
c) 4
d) 1
Answer: a

Question: In which of the following crystals alternate tetrahedral voids are occupied?
a) NaCl
b) ZnS
c) CaF₂
d) Na₂O
Answer: b

Question: An organic compound crystallises in an orthorhombic cell in the ratio of 2:1. The dimensions of the cell are 12.05, 15.05 and 2.69 Å and density is 1.419 g/cm³. Find the molar mass of the compound.
a) 207 g/mol
b) 209 g/mol
c) 308 g/mol
d) 317 g/mol
Answer: b

Question: Volume occupied by single CsCl ion pair in a crystal is 7.014 × 10⁻²³ cm³. The smallest Cs—Cs internuclear distance is nearly
a) 4.4 Å
b) 4.3 Å
c) 4 Å
d) 4.5 Å
Answer: c

Question: If ionic radius of Cs⁺ and Cl⁻ are 1.69 Å and 1.81 Å respectively, the edge length of unit cell is
a) 4.04 Å
b) 3.50 Å
c) 7.00 Å
d) None of these
Answer: a

Question: Copper crystallises in FCC lattice with a unit cell edge of 361 pm. The radius of copper atom is
a) 181 pm
b) 108 pm
c) 128 pm
d) 157 pm
Answer: c

Question: Lithium forms body-centred cubic structure. The length of the side of its unit cell is 351 pm. Atomic radius of lithium will be
a) 75 pm
b) 300 pm
c) 240 pm
d) 152 pm
Answer: d

Question: CsCl crystallises in body-centred cubic lattice. If ‘a’ is its edge length, then which of the following expression is correct?
a) rCs⁺ + rCl⁻ = 3a
b) rCs⁺ + rCl⁻ = 3a/2
c) rCs⁺ + rCl⁻ = √3 a / 2
d) rCs⁺ + rCl⁻ = √3 a
Answer: c

Question: The cubic unit cell of Al (molar mass 27 g/mol) has an edge length of 405 pm. Its density is 2.7 g/cm³. The cubic unit cell is
a) face centred
b) body centred
c) primitive
d) edge centred
Answer: a

Question: For AX ionic crystal to exist in BCC structure, the ratio of radii (r₍cation₎ / r₍anion₎) should be
a) between 0.41 and 0.73
b) greater than 0.73
c) less than 0.41
d) equal to 1.0
Answer: b

Question: What is the number of tetrahedral voids per atom in a crystal?
a) 1
b) 2
c) 6
d) 8
Answer: b

Question: Total volume of atoms present in a face-centred cubic unit cell of a metal is (r = atomic radius)
a) 20/3 π r³
b) 24/3 π r³
c) 12/3 π r³
d) 16/3 π r³
Answer: d

Question: In an antifluorite structure, cations occupy
a) octahedral voids
b) centre of cube
c) tetrahedral voids
d) corners of cube
Answer: c

Question: Which kind of defect is shown by the given crystal?
K⁺ Cl⁻ K⁺ Cl⁻ K⁺ Cl⁻
Cl⁻ Cl⁻ K⁺ K⁺
K⁺ Cl⁻ Cl⁻ K⁺ Cl⁻
Cl⁻ K⁺ Cl⁻ K⁺ K⁺
a) Schottky defect
b) Frenkel defect
c) Schottky and Frenkel defects
d) Substitution disorder
Answer: a

Question: If the radius of K⁺ and F⁻ are 133 pm and 136 pm respectively, the distance between K⁺ and F⁻ in KF is
a) 269 pm
b) 134.5 pm
c) 136 pm
d) 3 pm
Answer: a

Question: Copper crystallises in FCC with a unit cell length of 361 pm. What is the radius of copper atom?
a) 108 pm
b) 127 pm
c) 157 pm
d) 181 pm
Answer: b

Question: Which of the following has the highest value of energy gap?
a) Aluminium
b) Silver
c) Germanium
d) Diamond
Answer: d

Question: If we mix a pentavalent impurity in a crystal lattice of germanium, what type of semiconductor formation will occur?
a) p-type
b) n-type
c) Both a and b
d) None of these
Answer: b

Question: KCl crystallises in the same type of lattice as does NaCl. Given that rNa⁺ / rCl⁻ = 0.55 and rK⁺ / rCl⁻ = 0.74, the ratio of the side of the unit cell for KCl to that of NaCl is
a) 1.123
b) 0.0891
c) 1.414
d) 0.414
e) 1.732
Answer: a

Question: An ion leaves its regular site to occupy a position in the space between the lattice sites. This is called
a) Frenkel defect
b) Schottky defect
c) Impurity defect
d) Vacancy defect
Answer: a

Question: A metallic element has a cubic lattice. Each edge of the unit cell is 2 Å. The density of the metal is 2.5 g/cm³. The number of unit cells in 200 g of metal is
a) 1 × 10²⁴
b) 1 × 10²⁰
c) 1 × 10²²
d) 1 × 10²⁵
Answer: d

Question: Which of the following statements is correct?
a) Silicon doped with boron is an n-type semiconductor
b) Silicon doped with arsenic is a p-type semiconductor
c) Metals are good conductors of electricity
d) Electrical conductivity of semiconductors decreases with increasing temperature
Answer: c

Question: Schottky defect generally appears in
a) NaCl
b) KCl
c) CsCl
d) All of these
Answer: d

Question: 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)
a) 2.57 × 10²¹
b) 5.14 × 10²¹
c) 1.28 × 10²¹
d) 1.71 × 10²¹
Answer: a

Question: In orthorhombic, the value of a, b, and c are 4.2 Å, 8.6 Å, and 8.3 Å, respectively. Given the molecular mass of the solute is 155 g/mol and density is 3.3 g/cm³, the number of formula units per unit cell is
a) 2
b) 3
c) 4
d) 6
Answer: c

Question: Which one of the following defects in crystals lowers its density?
a) F-centres defect
b) Interstitial defect
c) Frenkel defect
d) Schottky defect
Answer: d

Question: The radius ratio (r⁺ / r⁻) of an ionic solid (A⁺B⁻) is 0.69. What is the coordination number of B⁻?
a) 6
b) 8
c) 2
d) 10
Answer: a

Question: A solid metal has CCP or FCC structure. The relation of side of cube (a) and radius of atom (r) will be
a) a = 2r
b) a = 2√2 r
c) a = 4 / √3 r
d) a = √3 / 2 r
Answer: b

Question: A metal has BCC structure and the edge length of its unit cell is 3.04 Å. The volume of the unit cell in cm³ will be
a) 1.6 × 10⁻²¹ cm³
b) 2.81 × 10⁻²³ cm³
c) 6.02 × 10⁻²³ cm³
d) 6.6 × 10⁻²⁴ cm³
Answer: b

Question: Which is the wrong statement regarding a crystal containing Schottky defect?
a) Electrical neutrality of the crystal is maintained
b) Entropy of the crystal increases
c) The density of the overall crystal remains the same
d) The density of the overall crystal reduces
Answer: c

Question: In a solid lattice, the cation has left a lattice site and is located at an interstitial position. The lattice defect is
a) Frenkel defect
b) Schottky defect
c) F-centre defect
d) Valency defect
Answer: a

Question: 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
a) 288 pm
b) 398 pm
c) 618 pm
d) 144 pm
Answer: d

Question: For a crystal, the angle of diffraction (2θ) is 90° and the second-order line has a d-value of 2.28 Å. The wavelength (in Å) of X-rays used for Bragg’s diffraction is
a) 1.612
b) 2.00
c) 2.28
d) 4.00
Answer: a

Question: The elements commonly used for making transistors are
a) C and Si
b) Ga and In
c) P and As
d) Si and Ge
Answer: d

Question: An ionic compound is expected to have tetrahedral structure if r⁺ / r⁻ lies in the range of
a) 0.414 to 0.732
b) 0.225 to 0.414
c) 0.155 to 0.225
d) 0.732 to 1
Answer: b

Question: The radius of Na⁺ and Cl⁻ ions are 95 pm and 181 pm respectively. The edge length of NaCl unit cell is
a) 276 pm
b) 138 pm
c) 552 pm
d) 415 pm
Answer: c

Question: Schottky defects occur mainly in electrovalent compounds where
a) Positive ions and negative ions are of different size
b) Positive ions and negative ions are of same size
c) Positive ions are small and negative ions are big
d) Positive ions are big and negative ions are small
Answer: b

Question: The flame colours of metal ions are due to
a) Frenkel defect
b) Schottky defect
c) Metal deficiency defect
d) Metal excess defect
Answer: d

Question: The first order reflection (n = 1) from a crystal of the X-ray from a copper anode tube (λ = 1.54 Å) occurs at an angle of 45°. What is the distance between the set of planes causing the diffraction?
a) 0.1089 nm
b) 0.1089 m
c) 0.905 Å
d) 1.089 × 10⁻⁹ m
Answer: c

Question: A metal crystallises in a BCC lattice. Its unit cell edge length is about 300 pm and its molar mass is about 50 g mol⁻¹. What would be the density of the metal (in g cm⁻³)?
a) 3.1
b) 6.2
c) 9.3
d) 12.4
Answer: b

Question: Sodium metal crystallises at room temperature in a body centred cubic lattice with a cell edge a = 4.29 Å. The radius of sodium atom is
a) 1.40 Å
b) 2.65 Å
c) 1.85 Å
d) 2.15 Å
Answer: c