Tiêu đề 1.THE SOLID STATE - Questions.pdf ✅

1.THE SOLID STATE (1.)Which of the following has highest value of energy gap? (a.) Aluminum (b.) Silver (c.) Germanium (d.) Diamond (2.)Which is not the correct statement for ionic solids in which positive and negative ions are held by strong electrostatic attractive forces? (a.) The radius r +/r − increases as coordination number increases (b.) As the difference in size of ions increases, coordination number increases (c.) When coordination number is eight, the r +/r − ratio lies between 0.225 to 0.414 (d.) In ionic solid of the type AX(ZnS, Wurtzite), the coordination number of Zn 2+andS 2− respectively are 4 and 4 (3.)The orthorhombic, the value of a, band care respectively 4.2 Å, 6.8A Å and 8.3 Å. Given the molecular mass of the solute is 155 g mol −1 and that of density is 3.3g/cc, the number of formula units per unit cell is (a.) 2 (b.) 3 (c.) 4 (d.) 6 (4.)A solid has structure in which ‘W’ atoms are located at the corners of a cubic lattice ‘O’ atoms at the centre of edge and Na atoms at the centre of cube. The formula for the compound is (a.) Na2WO3 (b.) Na2WO2 (c.) NaWO2 (d.) NaWO3 (5.)The ionic radii of Rb + and I − are 1.46 Å and 2.16 Å. The most probable type of structure exhibited by it is (a.) CsCl type (b.) ZnS type (c.) NaCl type (d.) CaF2 type (6.)Graphite is a (a.) Molecular solid (b.) Covalent solid (c.) Ionic solid (d.) Metallic solid (7.)In CsCl type structure the coordination number of Cs +and Cl− are (a.) 6, 6 (b.) 6, 8 (c.) 8, 8 (d.) 8, 6 (8.)In NaCl unit cell, all the ions lying along the axis as shown in the figure are removed. Then the number of Na + and Cl − ions remaining in the unit cell are (a.) 4 and 4 (b.) 3 and 3 (c.) 1 and 1 (d.) 4 and 3 (9.)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 plane causing the diffraction? (a.) 0.1089 nm (b.) 0.1089 m (c.) 0.905 Å (d.) 1.089 × 10−9m (10.)Iodine is a (a.) Electrovalent solid (b.) Atomic solid (c.) Molecular solid (d.) Covalent solid (11.)A metallic element has a cubic lattice. Each edge of the unit of cell is 2Å. The density of the metal is 2.5 g cm−3 . The unit cells in 200 g of metal are (a.) 1 × 1024 (b. ) 1 × 1020 (c.) 1 × 1022 (d. ) 1 × 1025 (12.)The number of hexagonal faces that are present in a truncated octahedron is (a.) 2 (b.) 4 (c.) 6 (d.) 8 (13.)In NaCl crystal each Cl − ion is surrounded by (a.) 4 Na + ions (b.) 6 Na + ions (c.) 1 Na + ion (d.) 2 Na + ions
(14.)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 anions is (a.) 288 pm (b.) 398 pm (c.) 618 pm (d.) 144 pm (15.)For AX ionic crystal to exist in bcc structure, the ratio of radii ( rcation ranions ) should be (a.) Between 0.41 and 0.73 (b.) Greater then 0.73 (c.) Less than 0.41 (d.) Equal to 1.0 (16.)Which of the following statements about amorphous solids is incorrect? (a.) They melt over a range of temperature (b.) They are anisotropic (c.) There is no orderly arrangement of particles (d.) They are rigid and incompressible (17.)A compound of ‘A’ and ‘B’ crystallises in a cubic lattice in which ‘A’ atoms occupy the lattice points at the corners of the cube. The ‘B’ atoms occupy the centre of each face of the cube. The probable empirical formula of the compound is (a.) AB2 (b.) A3B (c.) AB (d.) AB3 (18.)Which set of characteristics of ZnS crystal is correct? (a.) Coordination number (4 : 4): ccp; Zn 2+ ion in the alternate tetrahedral voids (b.) Coordination number (6 : 6); hcp; Zn 2+ ion in all tetrahedral voids (c.) Coordination number (6 : 4); hcp; Zn 2+ ion in all octahedral voids (d.) Coordination number (4 : 4); ccp; Zn 2+ ion in all tetrahedral voids (19.)Which has no rotation of symmetry? (a.) Hexagonal (b.) Orthorhombic (c.) Cubic (d.) Triclinic (20.)The coordination number of Na +inNaCl is (a.) 6 (b.) 8 (c.) 4 (d.) 1 (21.)Electrons in a paramagnetic compound are (a.) Shared (b.) Unpaired (c.) Donated (d.) Paired (22.)What is the structure of NaCl? (a.) BCC (b.) FCC (c.) Interpenetrating fcc (d.) None of these (23.)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 (24.)Schottky defects occurs 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 (25.)Which of the following statements is not correct? (a.) The units of surface tension are dynes Cm−1 (b.) The units of viscosity coefficient of a liquid are ‘poise ‘ (c.) CsCl crystallizes in body centred cubic type of lattice (d.) The coordination number of S 2− in ZnS is 6 (26.)Which one of the following defects in the crystals lowers its density? (a.) Frenkel defect (b.) Schottky defect (c.) F-centres (d.) Interstitial defect (27.)The axial angles in triclinic crystal system are (a.) α = β = γ = 90° (b.) α = γ = 90°, β ≠ 90° (c.) α ≠ β ≠ γ ≠ 90° (d.) α = β = γ ≠ 90° (28.)In the face centred cubic lattice, atom A occupies the corner positions and atom B occupies the face centre positions. If one atom of B is missing from one of the face centred points, the formula of the compound is (a.) A2B (b.) AB2 (c.) A2B2 (d.) A2B5 (29.)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 the two (30.)Doping of silicon (Si) with boron (B) leads to (a.) n −type semiconductor (b.) p −type semiconductor (c.) Metal (d.) Insulator (31.)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 (32.)A compound is formed by elements A and B. This crystallises in the cubic structure where the A atoms are at the corners of the cube and B atoms are at the body centres. The simplest formula of the compound is (a.) AB (b.) A6B (c.) A8B4 (d.) AB6 (33.)The radii 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 (34.)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 (35.)The number of atoms contained in a fcc unit cell of a monoatomic substance is (a.) 1 (b.) 2 (c.) 4 (d.) 6 (36.)The cubic unit cell of Al (molar mass 27 g mol−1 )has an edge length of 405 pm. Its density is 2.7 g cm−3 . The cubic unit cell is (a.) Face centred (b.) Body centred (c.) Primitive (d.) Edge centred (37.)Density of a crystal remains unchanged as a result of (a.) Ionic defect (b.) Schottky defect (c.) Frenkel defect (d.) Crystal defect (38.)The radius ratio of CsCl is 0.93. The expected lattice structure is (a.) Tetrahedral (b.) Square planar (c.) Octahedral (d.) Body centred cubic (39.)KCl crystallises in the same type of lattice as dose NaCl. Given that rNa+/rCl− = 0.55 and rK +/rCl− = 0.74. Calculate the ratio of the side of the unit cell for KCl to that of NaCl. (a.) 1.123 (b.) 0.0891 (c.) 1.414 (d.) 0.414 (40.)In which of the following crystals alternate tetrahedral voids are occupied? (a.) NaCl (b.) Zns (c.) CaF2 (d.) Na2O (41.)The elements commonly used for making transistors are (a.) C and Si (b.) Ga and In (c.) P and As (d.) Si and Ge (42.)Which element is used for making a transistor? (a.) Sn (b.) Sb (c.) Si (d.) Mg (43.)Which of the following statement is true? (a.) Some complex metal oxides behave as superconductor (b.) Zinc oxide can act as superconductor (c.) An impurity of tetravalent germanium in trivalent gallium creates electron deficiency (d.) A Frenkel defect is formed when an ion is displaced from its lattice site to an interstitial site (44.)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% (45.)What is the number of tetrahedral voids per atom in a crystal? (a.) 1 (b.) 2
(c.) 6 (d.) 8 (46.)What type of crystal defect is indicated in the diagram below? (a.) Frenkel defect (b.) Schottky defect (c.) Interstitial defect (d.) Frenkel and Schottky defects (47.)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 (48.)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 (49.)A metal crystallises in a bcc lattice. Its unit cell edge length is about 300 pm and its molar mass 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 (50.)The limiting radius ratio for tetrahedral shape is (a.) 0 to 0.155 (b.) 0.255 to 0.414 (c.) 0.155 to 0.225 (d.) 0.414 to 0.732 (51.)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 (52.)How many number of atoms are there in a cube based unit cell having one atom on each corner and two atoms on each body diagonal of cube (a.) 8 (b.) 6 (c.) 4 (d.) 9 (53.)The crystalline structure of NaCl is (a.) Hexagonal close packing (b.) Face centred cubic (c.) Square planar (d.) Body centred cubic (54.)If the distance between Na + and Cl − ions in sodium chloride crystal is X pm, the length of the edge of the unit cell is (a.) 4 X pm (b.) X/4 pm (c.) X/2 pm (d.) 2 X pm (55.)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 (56.)In a cubic structure of diamond which is made from Xand Y, where X atoms are at the corners of the cube and Y at the face centres of the cube. The molecular formula of the compound is (a.) X2Y (b.) X3Y (c.) XY2 (d.) XY3 (57.)The maximum proportion of available volume that can be filled by hard spheres in diamond is (a.) 0.52 (b.) 0.34 (c.) 0.32 (d.) 0.68 (58.)In an antifluorite structure, cations occupy (a.) Octahedral voids (b.) Centre of cube (c.) Tetrahedral voids (d.) Corners of cube (59.)Coordination number of Zn in ZnS (zinc blende) is (a.) 6 (b.) 4 (c.) 8 (d.) 12 (60.)The flame colours of metal ions are due to (a.) Frenkel defect (b.) Schottky defect (c.) Metal deficiency defect (d.) Metal excess defect