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InterviewSolution
This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 51. |
Iron adopts two different crystalline allotropic forms one at 1183 K and other one below 1183 K, which differ in structural units as bcc and fcc are known as `alpha` and `gamma` forms.. What would be the ratio of densities of these two forms (`gamma` and `alpha` ) ? Assume inter atomic distance remains same. |
| Answer» Correct Answer - 1.0887 | |
| 52. |
If the number of atoms per unit in a crystal is 2, the structure of crystal is:A. octahedralB. Body centred cubicC. Face centred cubic (fcc)D. Simple cubic |
| Answer» Correct Answer - B | |
| 53. |
Which of the following does not represent radius of the atom correctly ? (i)Simple cubic cell : Radius =`a/2` (ii)Face centred cubic cell:Radius = `a/(3sqrt3)` (iii)Body centred cubic cell:Radius =`sqrt3/4a`A. (i)B. (iii)C. (ii)D. (i) and (ii) |
| Answer» Correct Answer - C | |
| 54. |
The fraction of total volume occupied by the atom present in a simple cubic isA. `pi/4`B. `pi/6`C. `pi/(3sqrt2)`D. `pi/(4sqrt2)` |
| Answer» Correct Answer - B | |
| 55. |
Which of the following is ferromagnetic compound ?A. `BaTiO_3`B. `K_4Fe(CN)_6`C. `Pb_2^(-)O_3`D. `Al_2C_3` |
| Answer» Correct Answer - A | |
| 56. |
Solid `A` is a very hard electrical insulator in solid as well as in molten state and melts at extermely high temperature. What type of solid is it?A. Ionic solidsB. Covalent solidsC. Metallic solidsD. Molecular solids |
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Answer» Correct Answer - B Covalent solids or network solids are very hard with high melting point and are insulators in solid as well as in molten state. |
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| 57. |
The coordination number of Y will be A. 6B. 8C. 12D. 4 |
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Answer» Correct Answer - D Coordination no. of Y `(Zn^(2+))` is 4 |
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| 58. |
The unit cell shown in the figure belongs to A. NaCl typeB. ZnS typeC. CsCl typeD. `CaF_2` type |
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Answer» Correct Answer - B The unit cell is ZnS type where `S^(2-)` ions are present at the corners and at the centre of each face. `Zn^(2+)` ions occupy half of the tetrahedral sites . |
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| 59. |
Crystalline solids haveA. If both assertion and reason are true and reason is the correct explanation of assertionB. If both assertion and reason are true but reason is not the correct explanation of assertion.C. If assertion is true but reason is falseD. If both assertion and reason are false |
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Answer» Correct Answer - C Crystalline solids are anisotropic in nature that is , some of their physical properties like electrical resistance show different values along different directions due to different arrangement of particles in different directions. |
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| 60. |
Four solids W,X , Y and Z are given . All have a metallic lustre. The solids could be gold, lead sulphide , mica (which is quartz or `SiO_2`) and iodine . The results of the investigation are : (a)W is a good electrical conductor . X,Y and Z are poor electrical conductors (b)When the solids are hit with a hammer, W flattens out , X shaltters into many pieces, Y is smashed into a powder and Z is not affected . (c )When the solids are heated with a Bunsen burner, Y melts with some sublimation, but X, W and Z do not melt. (d)In treatment with `7M HNO_3`, X dissolves and there is no effect on W,Y or Z On the basis of these test results, identify the solids |
| Answer» X=PbS, `Y=I_2`, Z= Mica , W=Gold | |
| 61. |
Which of the following is an amorphous solidA. Graphite (C )B. Quartz glass `(SiO_2)`C. Chrome alumD. Silicon carbide (SiC) |
| Answer» Correct Answer - B | |
| 62. |
Which of the following do not matchA. Plastic : amorphous solidB. Graphite : Metallic solidC. `P_4O_10` : Molecular solidD. SiC-covalent solid |
| Answer» Correct Answer - B | |
| 63. |
What type of defects are represented by given figure ? A. Frenkel defectB. metal excess defectC. Cation deficiency defectD. Interstitial defect |
| Answer» Correct Answer - B | |
| 64. |
F-Centres are:A. fcc centerB. Metal deficiency defectC. Anion vacancy defectD. Face center |
| Answer» Correct Answer - C | |
| 65. |
Which of the following is a covalent solid ?A. Dry iceB. `P_4O_10`C. SiCD. NaCl |
| Answer» Correct Answer - C | |
| 66. |
Tetrahedral voids is surrounded by four atoms. Which atoms in the given figure are around the tetrahedral voids ? A. 2,3,4 and 5B. 1,3,4,5C. 1,2,3,4D. 2,4,5 |
| Answer» Correct Answer - C | |
| 67. |
Cations are present in the interstitial sites in …………… .A. Frenkel defectB. Schottky defectC. Vacancy defectD. metal deficiency defect |
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Answer» Correct Answer - A Frenkel defect is shown by ionic solids. The smaller ion ( usually cation) is dislocated from its interstitial site . |
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| 68. |
Coordinating number of `Na^(+)` in `NaCl` isA. 6B. 8C. 4D. 1 |
| Answer» Correct Answer - A | |
| 69. |
Body -centred cubic lattice has a corrdination number ofA. 4B. 6C. 12D. 8 |
| Answer» Correct Answer - D | |
| 70. |
which of the following is not a characteristic of a crystalline solid ?A. Definite and characteristic heat of fusionB. Isotropic natureC. A regular periodically repeated pattern of arrangement of constituent particles in the entire crystalD. A true solid |
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Answer» Correct Answer - B Crystalline solids are anisotropic in nature. |
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| 71. |
Statement-1:p-type semiconductor are formed due to metal excess defect. Statement-2: F-centres are created due to metal excess defect.A. Statement-1 is true, statement-2 is true, statement-2 is a correct explanation for statement-1B. Statement-1 is true, statement-2 is true, statement-2 is not correct explanation for statement-1C. Statement-1 is true, statement-2 is falseD. Statement-1 is false, statement-2 is true |
| Answer» Correct Answer - D | |
| 72. |
Statement-1:The coordination number of a cation present in an O void is 6 Statement-2:O-voids are formed due to overlapping of two trigonal voids of adjacent layers.A. Statement-1 is true, statement-2 is true, statement-2 is a correct explanation for statement-1B. Statement-1 is true, statement-2 is true, statement-2 is not correct explanation for statement-1C. Statement-1 is true, statement-2 is falseD. Statement-1 is false, statement-2 is true |
| Answer» Correct Answer - A | |
| 73. |
In a B.C.C. unit-cell of compound AB, A is located at cubical void. Calculate the ratio of the 4th C.N. and 3rd C.N. of A |
| Answer» Correct Answer - B | |
| 74. |
The number of atoms in a cubic based unit cell having one atom on each corner and two atoms on each body diagonal is |
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Answer» Number of atoms from 8 corners =`1/8xx8`=1 Number of atoms from 4 body diagonals = 2 x 4 =8 `therefore` Total number of atoms per unit cell = 9 |
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| 75. |
Malleability and ductility of metals can be accounted due toA. The capacity of layers of metal ions to slide over the otherB. The crystalline structure in metalC. Presence of electrostatic with metal ionsD. Interaction of electrons with metal ions. |
| Answer» Correct Answer - A | |
| 76. |
In the following figure , the blank X is known as ___ and why ? A. Electron trap , because an electron is present hereB. Metal deficient centre , since negative charge is present hereC. F-centre , since it imparts colour to the crystalD. F-centre, since it is responsible for positive charge on the crystal |
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Answer» Correct Answer - C The anionic sites occupied by the unpaired electrons are called F-centres from the German word Farbenzenter for colour centre. |
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| 77. |
When electron are trapped into the crystal in anion cancy ,the defect is known asA. F-centreB. Frenkel defectC. Schottky defectD. Interstitial defect |
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Answer» Correct Answer - A F-centres are electron trapped anion site which are responsible for colour. |
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| 78. |
Which of the following has highest number of formula units per unit cell ?A. NaCl type structureB. `Na_2O` type structureC. `CaF_2` type structureD. All have same number of formula unit |
| Answer» Correct Answer - D | |
| 79. |
Which defect causes decreases in the density of crystal?A. Schottky defectB. Frenkel defectC. Interstitial defectD. Metal excess defect |
| Answer» Correct Answer - A | |
| 80. |
A cubic unit cell has eight edge-centres. (true/false) |
| Answer» Correct Answer - False | |
| 81. |
IF the radius ratio of cation to anion is in the range of 0.225 - 0.414 , then the coordination number of cation will be _________.A. 3, plane triangularB. 6,octahedralC. 4,tetrahedralD. 8,cubic |
| Answer» Correct Answer - C | |
| 82. |
Total number of T-voids and O-voids in HCP and CCP structures are different . (True/False) |
| Answer» Correct Answer - True | |
| 83. |
Lithium metal crystallizes in a body centred cubic crystals. If the length of the side of the unit cell of lithium is `351p m` the atomic radius of the lithium will beA. 240.8 pmB. 151.9 pmC. 75.5 pmD. 300.5 pm |
| Answer» Correct Answer - B | |
| 84. |
Potassium crystallizes in a body centred cubic lattice. How many unit cells are present in 2g potassium ? (At. Mass of K=39) |
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Answer» A bcc unit cell has 2 lattice points per unit cell `therefore` Moles of potassium =`2/39` Number of atoms of K=`(2xx6.022xx10^23)/39` Number of unit cells=`(2xx6.022xx10^23)/(39xx2)=1.54xx10^22` |
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| 85. |
Potassium crystallizes in a body centred cubic lattice . What is the approximate number of unit cells in 4.0 gm of potassium ? (Atomic mass of potassium =39) |
| Answer» Correct Answer - `3.09xx10^22` | |
| 86. |
The volume of atom present in a face-centred cubic unit cell of a metal (`r` is atomic radius ) isA. `20/3 pir^3`B. `24/3 pir^3`C. `12/3 pir^3`D. `16/3 pir^3` |
| Answer» Correct Answer - D | |
| 87. |
Calculate the approximate number of unit cells present in 1 g of gold. Given that gold cyrstallises in a face centred cubic lathce (Given atomic mass of gold = 197 u). |
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Answer» Mole of Au=`1/197` Number of atoms of Au=`(6.022xx10^23)/197` Total number of unit cells =`(6.022xx10^23)/(197xx4)=7.64xx10^20` |
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| 88. |
The volume of atom present in a face-centred cubic unit cell of a metal (`r` is atomic radius ) isA. `12/3 pir^3`B. `16/3 pir^3`C. `20/3 pir^3`D. `24/3 pir^3` |
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Answer» Correct Answer - B `a=2sqrt2r` Volume of the cell =`a^3=(2sqrt2r)^3=16sqrt2r^3` No. of spheres in fcc = `8xx1/8+6xx1/2=4` Volume of 4 spheres = `4xx4/3pir^3=16/3pir^3` |
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| 89. |
Copper crystallises in fcc with a unit cell length of 361 pm. What is the radius of copper atom?A. 157 pmB. 181 pmC. 127 pmD. 108 pm |
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Answer» Correct Answer - C For fcc, `r=sqrt2/4 a =sqrt2/4xx361=(1.414xx361)/4`=127 pm |
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| 90. |
Thallium chloride TlCl crystallises in either a simple cubic lattice or fcc lattice of `Cl^-`ions with `Tl^+` ions in voids. If the density of solid is `7 "g/cm"^3` and edge length of unit cell is `3.85xx10^(-8)` cm. What is the geometry of unit cell ? (At. number of Tl=204.37 & Cl=35.5) |
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Answer» `Z=(rhoxxN_0xxa^3)/M` `Z=(7xx6.02xx10^23xx(3.85xx10^(-6))^3)/243.87=1` It means , it is a simple cubic lattice. |
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| 91. |
For two isomorphous crystals A and B , the ratio of density of A to that of B is 1.6 while the ratio of the edge length of B to that of A is 2. If the molar mass of crystal B is 200 g `mol^(-1)`, then that of crystal A isA. `"240 g mol"^(-1)`B. `"120 g mol"^(-1)`C. `"80 g mol"^(-1)`D. `"40 g mol"^(-1)` |
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Answer» Correct Answer - D Density of the unit cell , `rho=(ZxxM)/(a^3xxN_A)` Given: `rho_A/rho_B=1.6, a_B/a_A=2, M_B` =200 g/mol `rho_A=(ZxxM_A)/((a_A)^3xxN_0),rho_B=(ZxxM_B)/((a_B)^3xxN_0)` (Z will be same for isomorphous crystals.) `rho_A/rho_B=M_A/M_Bxx(a_B/a_A)^3 rArr 1.6=M_A/200xx(2)^3` `M_A=(1.6xx200)/8`=40 g/mol |
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| 92. |
A metal crystallizes into two cubic phases, face-centred cubic and body-centred cubic, which have unit cell lengths `3.5` and `3.0 A`, respectively. Calculate the ration of densities of fcc and bcc.A. `1.259:1`B. `1:1.259`C. `3:2`D. `1.142:1` |
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Answer» Correct Answer - A Unit cell length for fcc=3.5 Å Unit cell length for bcc = 3.0 Å `therefore` Density in fcc=`(n_1xx at.wt.)/(V_1xxN_A)` Density in bcc =`(n_2xxat.wt.)/(V_2xxN_A)` or `"Density (fcc)"/"Density (bcc)"=n_1/n_2xxV_2/V_1 =4/2xxV_2/V_1 [ {:(therefore , "for fcc,",n_1=4),(therefore , "for bcc,",n_2=2):}]` Volume of fcc = `V_1=a^3=(3.5xx10^(-8))^3cm^3` and volume for bcc =`V_2=a^3=(3.0xx10^(-8))^3 cm^3` `therefore "Density (fcc)"/"Density (bcc)"=(4xx(3.0xx10^(-8))^3)/(2xx(3.5xx10^(-8))^3)` =1.259 or 1.259:1 |
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| 93. |
In which of the following pairs, both the crystals are not of the same type ?A. Ice , Solid `CO_2`B. NaCl , BaOC. Mg,ArD. SiC, diamond |
| Answer» Correct Answer - C | |
| 94. |
Among solids highest mp is observed forA. Covalent solidsB. Ionic solidsC. Pseudo solidsD. Molecular solids |
| Answer» Correct Answer - A | |
| 95. |
Which of the following systems do not give correct discription of axial lengths and axial angles ?A. Hexagonal a=b`ne`c `alpha=beta=90^@, gamma=120^@`B. Tetragonal `a=bnec alpha =beta=gamma=90^@`C. Monoclinic `anebnec alpha=beta=gamma ne 90^@`D. Cubic a=b=c `alpha=beta=gamma =90^@` |
| Answer» Correct Answer - C | |
| 96. |
Which of the following is not correct for ionic crystalsA. They posses high mp and bp ?B. All are electrolyteC. Exhibit the property of isomorphismD. Exhibit directional properties of the bond |
| Answer» Correct Answer - D | |
| 97. |
The most unsysmmetrical and symmeterical systems are, respectively:A. Tetragonal, cubicB. Triclinic, cubicC. Rhombohedral, hexagonalD. Orthorhombic, cubic |
| Answer» Correct Answer - B | |
| 98. |
The ability of a substance to exist in two or more crstaline forms knows as:A. AmorphismB. isomorphismC. PolymorphismD. isomerism |
| Answer» Correct Answer - C | |
| 99. |
In a tetragonal crystalA. `a=b=c " " alpha=beta=gamma=90^@`B. `a=bnec " " alpha=beta=gamma=90^@`C. `anebnec " " alpha=beta=gamma=90^@`D. `anebnec " " alpha=beta=gammane90^@` |
| Answer» Correct Answer - B | |
| 100. |
In which of the following pairs both the solids belong to same type ?A. SiC, AlNB. `CaF_2, Ca`C. Graphite , IceD. Solid `CO_2` , ZnS |
| Answer» Correct Answer - A | |