Solid State:- 50 MCQ
Q. 1. Which of the following is not true about the ionic solids?
(A) Bigger ions form the close packed structure.
(B) Smaller ions occupy either the tetrahedral or the octahedral voids depending upon their size.
(C) Occupation of all the voids is not necessary.
(D) The fraction of octahedral or tetrahedral voids occupied depends upon the radii of the ions occupying the voids.
Ans. Option (B) is correct. Explanation: In ionic solids, smaller ions occupy the voids, and this depends on stoichiometry of the compounds not on the radius of ions.
Q. 2. Solid A is very hard electrical insulator in solid as well as in molten state and melts at an extremely high temperature. What type of solid is it?
(A) Ionic solid
(B) Molecular solid
(C) Covalent solid
(D) Metallic solid
Ans. Option (C) is correct. Explanation: Covalent solids are generally hard, act as insulators and melting points of such solids are extremely high
Q. 3. Which of the following is a network solid?
(A) SO2(solid)
(B) I2
(C) Diamond
(D) H2O (ice)
Ans. Option (C) is correct. Explanation: A network solid consists of a network atom of same or different elements connected to each other by covalent bonds. So, diamond is a network solid as it contains network of carbon atoms
4. Graphite cannot be classified as __________.
(A) Conducting solid
(B) Network solid
(C) Covalent solid
(D) Ionic solid
Ans. Option (D) is correct. Explanation: Graphite is a conducting solid, network or covalent solid but it cannot be classified as ionic solid.
Q. 5. Which of the following statements is not true about amorphous solids?
(A) On heating they may become crystalline at certain temperature.
(B) They may become crystalline on keeping for long time.
(C) Amorphous solids can be molded by heating.
(D) They are anisotropic in nature.
Ans. Option (D) is correct. Explanation: Amorphous solids are isotropic in nature, i.e., there is no long-range order, and arrangement is irregular along all the directions.
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Q. 6. Which of the following is an amorphous solid?
(A) Graphite
(B) Quartz glass (SiO2)
(C) Chrome alum
(D) Silicon carbide (SiC)
Ans. Option (B) is correct. Explanation: Quartz glass (SiO2) is an amorphous solid as it has no long-range order.
Q. 7. The sharp melting point of crystalline solids is due to ___________.
(A) a regular arrangement of constituent particles observed over a short distance in the crystal lattice.
(B) a regular arrangement of constituent particles observed over a long distance in the crystal lattice.
(C) same arrangement of constituent particles in different directions.
(D) different arrangements of constituent particles in different directions.
Ans. Option (B) is correct. Explanation: The sharp melting point of crystalline solids is due to a regular arrangement of constituent particles observed over a long distance in the crystal lattice.
Q. 8. Which of the following conditions favours the existence of a substance in the solid state?
(A) High temperature
(B) Low temperature
(C) High thermal energy
(D) Weak cohesive forces
Ans. Option (B) is correct. Explanation: At low temperature substance exists in solid state. It is due to the decrease in molecular movement which leads to strong cohesive force, that is, the force which tightly holds the constituent particles together.
Q. 9. A compound is formed by two elements M and N. The element N forms ccp lattice and atoms of M occupy 1/3rd of tetrahedral voids. What is the formula of the compound?
(A) MN2 (B) M2N3(C) M3N2 (D) M2N2
Ans. Option (B) is correct. Explanation: Suppose the atoms N in the ccp = a
No. of tetrahedral voids = 2a
No. of atoms M = 2a x 1/3
M :N
(2a x 1/3) : a
or
a = 2: 3
Hence compound as M2N3
Q. 10. Silver crystallises in f.c.c. Lattice. It edge length of the unit cells is 4.07 × 10–8 cm density and is 10.5g cm–3. Calculate the atomic mass of silver.
(A) 144 g/mol
(B) 125 g/mol
(C) 106.6 g/mol
(D) 213 g/mol
Ans. Option (C) is correct
Q. 11 The correct order of the packing efficiency in different types of unit cells is ________.
(A) fcc < bcc < simple cubic
(B) fcc > bcc > simple cubic
(C) fcc < bcc > simple cubic
(D) bcc < fcc = simple cubic
Ans. Option (B) is correct. Explanation: The correct order of the packing efficiency in different types of unit cells is given below: Unit Cell Packing efficiency fcc 74% bcc 68% Simple cubic 52.4% fcc > bcc > simple cubic
Q. 12. The total number of tetrahedral voids in the face centred unit cell is _____.
(A) 6
(B) 8
(C) 10
(D) 12
Ans. Option (B) is correct. Explanation: The total number of tetrahedral voids in the face centred unit cell is 8.
Q. 13. The lattice site in a pure crystal cannot be occupied by __________.
(A) Molecule
(B) Ion
(C) Electron
(D) Atom
Ans. Option (C) is correct. Explanation: Each point in a lattice is known as lattice point which can be either atom, molecule or ion. It is joined together by a straight line to bring out geometry of lattice in pure crystal constituents. They are arranged in fixed stoichiometric ratio. Hence, existences of free electrons are not possible.
Q. 14. Which of the following statements is not true about the hexagonal close packing?
(A) The coordination number is 12.
(B) It has 74% packing efficiency.
(C) Tetrahedral voids of the second layer are covered by the spheres of the third layer.
(D) In this arrangement spheres of the fourth layer are exactly aligned with those of the first layer
Ans. Option (D) is correct: – Explanation: Hexagonal close packing (hcp) can be arranged by two layers A and B one over another which can be diagrammatically represented as: In the above figure the first layer and fourth are not exactly aligned. Thus, statement (D) is not correct while other statements, i.e., (A), (B) and (C) are true
Q. 15. In which of the following structures coordination number for cations and anions in the packed structure will be same?
(A) Cl– ion form fcc lattice and Na+ ions occupy all octahedral voids of the unit cell.
(B) Ca2+ ions form fcc lattice and F– ions occupy all the eight tetrahedral voids of the unit cell.
(C) O2– ions form fcc lattice and Na+ ions occupy all the eight tetrahedral voids of the unit cell.
(D) S2– ions form fcc lattice and Zn2+ ions go into alternate tetrahedral voids of the unit cell
Ans. Option (A) is correct. Explanation: NaCl unit cell has a fcc structure of Cl–ions, and Na+ ions occupy octahedral voids. The radius ratio of 0.524 for NaCl suggests an octahedral void
Q. 16. What is the coordination number in a square close packed structure in two dimensions?
(A) 2
(B) 3
(C) 4
(D) 6
Ans. Option (C) is correct. Explanation: In square close packing in two dimensions each sphere is in contact with four of its neighbours. Thus, its coordination number is 4.
17. The appearance of colour in solid alkali metal halides in generally due to
(a) Schottky defect (b) Frenkel defect (c) Interstitial position (d) F-center
ANS: (d) It is due to presence of unpaired electron forming F-center.
18. A given metal crystallizes 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?
(a) 80 pm
(b) 108 pm
(c) 40 pm
(d) 127 pm
Ans
(a) 527 pm (b) 264 pm (c) 154 pm (d) 352 pm
ANS:
a3 = 43.5 × 10–24 cm3
a3= 3.52 × 10–8 cm
= 352 pm
20. A metal crystallises in a face centred cubic structure. If the edge length of its unit cell is ‘a’, the closest approach between two atoms in metallic crystal will be
Ans:- (d) Closest approach distance between two atoms = 2r In fcc, 4r = 
21. The white ZnO turns yellow on heating because of
(a) Frenkel defect
(b) Metal excess defect
(c) Metal deficiency defect
(d) Schottky defect
ANS: (b) It is due to metal excess defect because some oxygen is lost to atmosphere. ∴ Zn2+ will become in excess. ZnO = Zn+2 + O2+ 2e–
22. In fcc, what is volume occupied?
23. An element crystallises in bcc lattice has an edge length 500 pm. If its density is 4 cm–3, the atomic mass of the element is g mol–1is [NA = 6 × 1023 mol–1]
(a) 100
(b) 250
(c) 125
(d) 150
Ans:- (d)
24. Which of the following crystals has unit cell such that a ≠ b ≠ c, α ≠ β ≠ γ ≠ 90
(a) K2Cr2O7
(b) NaNO3
(c) KNO3
(d) A8B7
ANS: (a) K2Cr2O7has triclinic crystal which has all sides unequal and all angles not equal to 90°.
25. Which of the following is wrong statement for cubic close packed (ccp) in three-dimensional structure is (are)
(a) the number of nearest neighbours of an atom present in the top most layer is 12.
(b) the efficiency is 74%.
(c) the number of octahedral and tetrahedral voids per atom are 1 and 2 respectively.
(d) the unit cell edge length is 2 times the radius of the atom.
ANS: (a) is not correct. In topmost layer it is 6.
26. Which of the following solids is not an electrical conductor?
(A) Mg(s) (B)TiO(s) (C) I2(s) (D) H2O(s)
(a) (A) only
(b) (B) Only
(c) (C) and (D)
(d) (B), (C) and (D)
ANS: (c) I2(s) is molecular solid does not have free electrons, it is insulator.
27. The total number of tetrahedral voids in the face centred unit cell is __________.
(a) 6
(b) 8
(c) 10
(d) 12
ANS: (b) Numbers of tetrahedral voids = 2 × Numbers of atoms = 2 × 4 = 8. [∵ Z = 4 for fcc]
28. In which pair most efficient packing is present?
(a) hcp and bcc (b) hcp and ccp (c) bcc and ccp (d) bcc and simple cubic cell
ANS: (b) Both hcp and ccp have packing efficiency 74%.
29. Which kind of defects are introduced by doping?
(a) Dislocation defect (b) Schottky defect (c) Frenkel defects (d) Electronic defects
ANS: (d) Electronic defects are introduced.
30. What is number of atoms present in 200 g of an element having bcc structure having edge length 300 pm and density 70 g cm–3?
(a) 8.12 × 1023 (b) 6.12 × 1022(c) 2.12 × 1024(d) 4.12 × 1025
Ans:-(c)
31. Which of the following is not true about the voids formed in 3-dimensional hexagonal close packed structure?
(a) A tetrahedral void is formed when a sphere of the second layer is present above triangular void in the first layer.
(b) All the triangular voids are not covered by the spheres of the second layer.
(c) Tetrahedral voids are formed when the triangular voids in the second layer lie above the triangular voids in the first layer and the triangular shapes of these voids do not overlap.
(d) Octahedral voids are formed when the triangular voids in the second layer exactly overlap with similar voids in the first layer.
ANS: (c) and (d) do not lead to formation of tetrahedral and octahedral respectively.
32. Under the influence of electric field, which of the following statements is true about the movement of electrons and holes in a p-type semiconductor?
(a) Electron will move towards the positively charged plate through electron holes.
(b) Holes will appear to be moving towards the negatively charged plate.
(c) Both electrons and holes appear to move towards the positively charged plate.
(d) Movement of electrons is not related to the movement of holes.
ANS: (a) and (b) are correct because electrons will be attracted towards +ve plate, holes are electron deficient and move towards the positively charged plate.
33. Match the defects given in Column I with the statements in given Column II.
|
Column I |
Column II |
|
(a) Simple vacancy defect |
(i) shown by non-ionic solids and increases density of the solid. |
|
(b) Simple interstitial defect |
(ii) shown by ionic solids and decreases density of the solid. |
|
(c) Frenkel defect |
(iii) shown by non- ionic solids |
|
(d) Schottky defect |
(iv) shown by ionic solids and density of the solid remains the same. |
ANS: (a) (iii) (b) (i)(c) (iv) (d) (ii)
34. Which of the following oxides behaves as conductor or insulator depending upon temperature?
(a) TiO (b) SiO2(c) TiO3 (d) MgO
ANS: (c) TiO3 behaves as conductor at high temperature.
35. Which of the following oxides shows electrical properties like metals?
(a) SiO2 (b) MgO (c) SO2(s) (d) CrO2
ANS: (d) CrO2 because it has unpaired electrons in d-orbitals which can move.
36. Cations are present in the interstitial sites in __________.
(a) Frenkel defect (b) Schottky defect (c) Vacancy defect (d) Metal deficiency defect
ANS: (a) In Frenkel defect cations are present in voids or interstitial sites due to smaller size.
37. Which of the following is true about the charge acquired by p-type semiconductors?
(b) neutral
(c) negative
(d) depends on concentration of p impurity
ANS: (b) Neutral, a hole is created which moves like positive charge.
38. Match the items given in Column I with the items given in Column II.
|
Column I |
Column II |
|
(a) Mg in solid state |
(i) p-Type semiconductor |
|
(b) MgCl2 in molten state |
(ii) n-Type semiconductor |
|
(c) Silicon with phosphorus |
(iii) Electrolytic conductors |
|
(d) Germanium with boron |
(iv) Electronic conductors |
ANS: (a) (iv) (b) (iii) (c) (ii) (d) (i)
39. Match the type of packing given in Column I with the items given in Column II.
|
Column I |
Column II |
|
(a) Square close packing in two dimensions |
(i) Triangular voids |
|
(b) Hexagonal close packing in two dimensions |
(ii) Pattern of spheres is repeated in every fourth layer |
|
(c) Hexagonal close packing in three dimensions |
(iii) Coordination number 4 |
|
(d) Cubic close packing in three dimensions |
(iv) Pattern of sphere is repeated in alternate layers |
ANS: (a) (iii) (b) (i) (c) (iv) (d) (ii)
40. Match the types of defects given in Column I with the statement given in Column II
41. In the following questions a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices.
(a) Assertion and reason both are correct statements and reason is correct explanation for assertion.
(b) Assertion and reason both are correct statements but reason is not correct explanation for assertion.
(c) Assertion is correct statement but reason is wrong statement.
(d) Assertion is wrong statement but reason is correct statement.
Assertion: The packing efficiency is maximum for the fcc structure.
Reason: The coordination number is 12 in fcc structures.
ANS: (b) Assertion and reason both are correct statements but reason is not correct explanation for assertion.
42. In the following questions a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices.
(a) Assertion and reason both are correct statements and reason is correct explanation for assertion.
(b) Assertion and reason both are correct statements but reason is not correct explanation for assertion. (c) Assertion is correct statement but reason is wrong statement.
(d) Assertion is wrong statement but reason is correct statement.
Assertion: Semiconductors are solids with conductivities in the intermediate range from 10–6– 104 ohm–1m–1.
Reason: Intermediate conductivity in semiconductor is due to partially filled valence band.
ANS:(c) Assertion is correct statement but reason is wrong statement.
43. In the following questions a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices.
(a) Assertion and reason both are correct statements and reason is correct explanation for assertion.
(b) Assertion and reason both are correct statements but reason is not correct explanation for assertion. (c) Assertion is correct statement but reason is wrong statement.
(d) Assertion is wrong statement but reason is correct statement.
Assertion: The total number of atoms present in a simple cubic unit cell is one.
Reason: Simple cubic unit cell has atoms at its corners, each of which is shared between eight adjacent unit cells.
ANS: (a) Assertion and reason both are correct statements and reason is correct explanation for assertion.
44.In the following questions a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices.
(a) Assertion and reason both are correct statements and reason is correct explanation for assertion.
(b) Assertion and reason both are correct statements but reason is not correct explanation for assertion. (c) Assertion is correct statement but reason is wrong statement.
(d) Assertion is wrong statement but reason is correct statement.
Assertion: Graphite is a good conductor of electricity however diamond belongs to the category of insulators.
Reason: Graphite is soft in nature on the other hand diamond is very hard and brittle. 3
ANS:(b) Assertion and reason both are correct statements but reason is not correct explanation for assertion.
45. In the following questions a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices.
(a) Assertion and reason both are correct statements and reason is correct explanation for assertion.
(b) Assertion and reason both are correct statements but reason is not correct explanation for assertion. (c) Assertion is correct statement but reason is wrong statement.
(d) Assertion is wrong statement but reason is correct statement.
Assertion: Total number of octahedral voids present in unit cell of cubic close packing including the one that is present at the body centre, is four.
Reason: Besides the body centre there is one octahedral void present at the centre of each of the six faces of the unit cell and each of which is shared between two adjacent unit cells
ANS: (c) Assertion is correct statement but reason is wrong statement.
46. In the following questions a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices.
(a) Assertion and reason both are correct statements and reason is correct explanation for assertion.
(b) Assertion and reason both are correct statements but reason is not correct explanation for assertion. (c) Assertion is correct statement but reason is wrong statement.
(d) Assertion is wrong statement but reason is correct statement.
Assertion (A): LiCl Crystal is pink.
Reason (R): Pink colour of LiCl crystal is due to excess Lithium.
Ans. Option (A) is correct.
47. Which of the following Defects is also known as dislocation defect?
(A) Frenkel defect
(B) Schottky defect
(C) Non-stoichiometric defect
(D) Simple interstitial defect
Ans. Option (A) is correct. Explanation: Frenkel defect is also known as dislocation defect because in this defect one of the ion is missing from its lattice site and occupies an interstitial site.