A solid AB has NaCl structure. If the radius of action \[{{A}^{+}}\] is 170 pm, calculate the maximum possible radius of the anion \[{{B}^{-}}\]
A)
210.3 pm done
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B)
397.4 pm done
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C)
410.6 pm done
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D)
347.9 pm done
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If NaCl is doped with mol% \[SrC{{l}_{2}},\] what is the concentration of cation vacancies?
A)
\[6.02\times {{10}^{18}}mo{{l}^{-1}}\] done
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B)
\[6.02\times {{10}^{19}}mo{{l}^{-1}}\] done
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C)
\[6.02\times {{10}^{23}}mo{{l}^{-1}}\] done
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D)
\[6.02\times {{10}^{26}}mo{{l}^{-1}}\] done
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In a cubic dosed packed structure of mixed oxides, the lattice is made up of oxide ions, one eighth of tetrahedral/voids are occupied by divalent ions \[({{A}^{2+}}),\] while one half of the octahedral voids are occupied by trivalent ions \[({{B}^{3+}})\]. What is the formula of the oxide?
A)
\[{{A}_{3}}{{B}_{2}}{{O}_{4}}\] done
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B)
\[{{A}_{2}}{{B}_{2}}{{O}_{4}}\] done
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C)
\[A{{B}_{2}}{{O}_{5}}\] done
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D)
\[A{{B}_{2}}{{O}_{4}}\] done
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The composition of sample of wustite is \[F{{e}_{0.93}}{{O}_{1.00}}\]. What percentage of the iron is present in the form of Fe (III)?
A)
14% done
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B)
15.05% done
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C)
17% done
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D)
29% done
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In fcc lattice, A, B, C, D atoms are arranged at corners, face centres, octahedral voids and tetrahedral voids respectively, then the body diagonal contains
A)
2A, C, 2D done
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B)
2A, 2B, 2C done
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C)
2A, 2B, D done
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D)
2A, 2D done
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Which of the following order is correct regarding size of the voids.
A)
Octahedral < tetrahedral < square planar < trigonal done
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B)
trigonal < tetrahedral = square planar < octahedral done
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C)
trigonal < tetrahedral < square planar = octahedral done
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D)
tetrahedral < trigonal = square planar <octahedral done
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In which of the following unit cells all sides and all angles are equal? Cubic (I), Tetragonal (II), Orthorhombic (III), Rhombohedra (IV)
A)
I and II done
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B)
I done
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C)
I and III done
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D)
I and IV done
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Which of the following represents correct order of conductivity in solids?
A)
\[{{\kappa }_{\text{metals}}}>>{{\kappa }_{\text{insulators}}}<{{\kappa }_{\text{semiconductors}}}\] done
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B)
\[{{\kappa }_{\text{metals}}}<<{{\kappa }_{\text{insulators}}}<{{\kappa }_{\text{semiconductors}}}\] done
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C)
\[{{\kappa }_{\text{metals}}};{{\kappa }_{\text{semiconductors}}}<{{\kappa }_{\text{insulators}}}=\text{zero}\] done
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D)
\[{{\kappa }_{\text{metals}}}<{{\kappa }_{\text{semiconductors}}}>{{\kappa }_{\text{insulators}}}\ne \text{zero}\] done
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Match the type of packing given in Column-I with the items given in Column-II.
Column-I
Column-II
[a] Square close packing two dimensions
(1) Triangular voids
[b] Hexagonal close packing in two dimensions
(2) Pattern of sphere is repeated in every fourth layer.
[c] Hexagonal close packing in three dimensions
(3) Coordination number 4
[d] Cubic close packing in three dimensions
(4) Pattern of sphere is repeated in alternate layers.
A)
A-3, B-1, C-4, D-2 done
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B)
A-1, B-2, C-3, D-4 done
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C)
A-3, B-2, C-1, D-4 done
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D)
A-4, B-3, C-2, D-1 done
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Ferrous oxide has a cubic structure and each edge of the unit cell is \[5.0\text{ }{{A}^{o}}\]. Assuming density of the oxide as \[4.0\text{ }g\text{ }c{{m}^{-3}}\] the number of \[F{{e}^{2+}}\] and \[{{O}^{2-}}\] ions present in each unit cell will be
A)
two \[F{{e}^{2+}}\] and four \[{{O}^{2-}}\] done
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B)
three \[F{{e}^{2+}}\] and three \[{{O}^{2-}}\] done
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C)
four \[F{{e}^{2+}}\] and two \[{{O}^{2-}}\] done
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D)
four \[F{{e}^{2+}}\] and four \[{{O}^{2-}}\] done
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Which solid will have the weakest intermolecular forces?
A)
Ice done
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B)
Phosphorus done
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C)
Naphthalene done
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D)
Sodium fluoride done
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In normal spinel structures \[MgA{{l}_{2}}{{O}_{4}},\] the percentage of tetrahedral void occupied is
A)
12.5% done
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B)
25% done
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C)
50% done
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D)
None of these done
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\[ZnO\] is white when cold and yellow when heated. It is due to the development of
A)
Frenkel defect done
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B)
Schottky defect done
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C)
Metal excess defect done
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D)
Metal deficiency defect done
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A ferromagnetic substance becomes a permanent magnet when it is placed in a magnetic field because
A)
all the domains get oriented in the direction of magnetic field done
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B)
all the domains get oriented in the direction opposite to the direction of magnetic field done
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C)
domains get oriented randomly done
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D)
domains are not affected by magnetic field done
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A metallic element has a cubic lattice. Each edge of the unit cell is \[2{{A}^{0}}\]. The density of the metal is \[2\text{ }g\text{ }c{{m}^{-3}}\]. The unit cells in 200 g of the metal are
A)
\[1\times {{10}^{25}}\] done
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B)
\[1\times {{10}^{24}}\] done
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C)
\[1\times {{10}^{22}}\] done
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D)
\[1\times {{10}^{20}}\] done
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Which of following is an example of ionic crystalline solid?
A)
Diamond done
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B)
LiF done
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C)
Li done
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D)
Silicon done
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Which of the following statements about amorphous solids
A)
They melt over a range of temperature done
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B)
They are isotropic done
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C)
There is no orderly arrangement of particles done
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D)
They are rigid and incompressible done
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DIRECTION: Read the passage given below and answer the questions that follows: In hexagonal systems of crystals, a frequently encountered arrangement of atoms is described as a hexagonal prism. Here, the top and bottom of the cell are regular hexagons and three atoms sandwiched in between them. A space-of this model of this structure, called hexagonal close-packed (HCP), is constituted of a sphere on a flat surface surrounded in the same plane by six identical spheres as closely as possible. There spheres are then placed over the first layer so that they touch each other and represent the second layer. Each one of these three spheres touches three spheres of the bottom layer. Finally, the second layer is covered with third layer that is identical to the bottom layer in relative position. Assume radius of every sphere to be 'r'. The number of atoms in the HCP unit cell is
A)
4 done
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B)
6 done
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C)
12 done
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D)
17 done
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DIRECTION: Read the passage given below and answer the questions that follows: In hexagonal systems of crystals, a frequently encountered arrangement of atoms is described as a hexagonal prism. Here, the top and bottom of the cell are regular hexagons and three atoms sandwiched in between them. A space-of this model of this structure, called hexagonal close-packed (HCP), is constituted of a sphere on a flat surface surrounded in the same plane by six identical spheres as closely as possible. There spheres are then placed over the first layer so that they touch each other and represent the second layer. Each one of these three spheres touches three spheres of the bottom layer. Finally, the second layer is covered with third layer that is identical to the bottom layer in relative position. Assume radius of every sphere to be 'r'. The volume of this HCP units cell is-
A)
\[24\sqrt{2}{{r}^{3}}\] done
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B)
\[16\sqrt{2}{{r}^{3}}\] done
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C)
\[12\sqrt{2}{{r}^{3}}\] done
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D)
\[\frac{64}{3\sqrt{3}}{{r}^{3}}\] done
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DIRECTION: Read the passage given below and answer the questions that follows: In hexagonal systems of crystals, a frequently encountered arrangement of atoms is described as a hexagonal prism. Here, the top and bottom of the cell are regular hexagons and three atoms sandwiched in between them. A space-of this model of this structure, called hexagonal close-packed (HCP), is constituted of a sphere on a flat surface surrounded in the same plane by six identical spheres as closely as possible. There spheres are then placed over the first layer so that they touch each other and represent the second layer. Each one of these three spheres touches three spheres of the bottom layer. Finally, the second layer is covered with third layer that is identical to the bottom layer in relative position. Assume radius of every sphere to be 'r'. The empty space in this HCP unit cell is
A)
74% done
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B)
47.6% done
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C)
32% done
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D)
26% done
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Iron crystallizes in several-modifications. At about \[910{}^\circ C\] 'bcc' form (called \[\alpha -\]form) undergoes transitions, to \[\gamma -\]form with 'fcc' lattice. Assuming that the distance between the nearest neighbors is the same in the two forms at the transition temperature, calculate the ratio of the density of \[\gamma -\]ron to that of \[\alpha -\]iron at the transition temperature.
A)
0.0887 done
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B)
1.0887 done
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C)
1.546 done
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D)
1.544 done
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How many unit cells are present in a cube-shaped ideal crystal of \[NaCl\] of mass 1.00g? [Atomic masses: Na = 23, Cl = 35.5]
A)
\[2.57\times {{10}^{21}}\] unit cells done
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B)
\[5.14\times {{10}^{21}}\] unit cells done
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C)
\[1.28\times {{10}^{21}}\] unit cells done
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D)
\[1.71\times {{10}^{21}}\] unit cells done
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A metal crystallizes into two cubic phases, face centred cubic (fee) and body centred cubic (bcc) whose unit cell lengths are 3.5 and \[3.0\,\overset{o}{\mathop{A}}\,\] respectively. Calculate the ratio of the densities of fee and bee.
A)
1.67 done
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B)
1.26 done
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C)
6.23 done
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D)
1.04 done
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A compound formed by elements A and B has a cubic structure in which A atoms are at the comers of the cube and B atoms are at the face centres. The formula for the compound is
A)
\[{{A}_{2}}{{B}_{3}}\] done
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B)
\[A{{B}_{3}}\] done
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C)
\[{{A}_{3}}B\] done
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D)
\[{{A}_{3}}{{B}_{2}}\] done
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When heated above \[916{}^\circ C,\] iron changes its bcc crystalline form to fcc without the change in the radius of atom. The ratio of the density of the crystal before heating and after heating is:
A)
1.069 done
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B)
0.918 done
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C)
0.725 done
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D)
1.231 done
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The first three nearest neighbor distance for primitive cubic lattice are respectively (edge length of unit cell = a):
A)
\[a,\,\sqrt{2}a,\sqrt{3}a\] done
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B)
\[\sqrt{3}a,\,\sqrt{2}a,\,a\] done
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C)
\[a,\,\sqrt{2}a,2\,a\] done
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D)
\[a,\,\sqrt{3}a,2\,a\] done
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A crystal is made of particles A and B. A forms fcc packing and B occupies all the octahedral voids. If all the particles along the plane as shown in the figure are removed, then the formula of the crystal would be:
A)
\[AB\] done
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B)
\[{{A}_{5}}{{B}_{7}}\] done
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C)
\[{{A}_{7}}{{B}_{5}}\] done
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D)
none of these done
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Schottky defect in crystals is observed when
A)
unequal number of cations and anions are missing from the lattice. done
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B)
equal number of cations and anions are missing from the lattice. done
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C)
an ion leaves its normal site and occupies an interstitial site. done
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D)
density of the crystal is increased done
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List-I and List-II contains four entries each. Entries of List-I are to be matched with some entries of List-II. One or more than one entries of List-I may have the matching with the same entries of List-II.
List-I List-II [a] Rock salt structure (p) General formula is AB [b] Zinc blende structure (q) General formula is \[A{{B}_{3}}\] [c] Fluorite structure (r) General formula is \[{{A}_{2}}B\] [d] Anti fluorite structure (s) General formula is \[A{{B}_{2}}\]
A)
A-p, B-p, C-s, D-r done
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B)
A-q, B-q, C-p, D-s done
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C)
A-r, B-p, C-r, D-s done
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D)
A-s, B-s, C-p, D-q done
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In hexagonal close packing of sphere in three dimensions, which of the following statements is correct.
A)
In one unit cell there are 12 octahedral voids and all are completely inside the unit cell. done
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B)
In one unit cell there are six octahedral voids and all are completely inside the unit cell. done
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C)
In one unit cell there are six octahedral void and of which three are completely inside the unit cell and other three are partially inside the unit cell. done
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D)
In one unit cell there are 12 tetrahedral voids, all are completely inside the unit cell. done
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Percent of octahedral voids vacant in a perfect crystal of ZnS is
A)
0% done
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B)
50% done
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C)
100% done
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D)
25% done
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Lithium borohydride crystallizes in an orthorhombic system with 4 molecules per unit cell. The unit cell dimensions are \[a=6.8\text{ }\overset{o}{\mathop{A}}\,,\,b=4.4\overset{o}{\mathop{A}}\,\] and \[c=7.2\overset{o}{\mathop{A.}}\,\] If the molar mass is 21.76, then the density of crystals is:
A)
\[0.6708\text{ }g\text{ }c{{m}^{-2}}\] done
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B)
\[1.6708\text{ }g\text{ }c{{m}^{-3}}\] done
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C)
\[2.6708\text{ }g\,\,c{{m}^{-3}}\] done
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D)
None of these. done
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Column A describes nature of bonding and Column B the solid having that type of bonding:
A (Nature of bonding) B (solid) I. Van der Waals P. Al, Cd II. Ionic Q. \[C{{O}_{2}},{{H}_{2}}\] III. Metallic R. Si diamond IV. Covalent S. \[MgO,NaCl\]
Correct matching of A and B is in alternate:
A)
I-P, II-Q, III-R, IV-S done
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B)
I-Q, II-S, III-P, IV-R done
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C)
I-Q, II-P, III-R, IV-S done
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D)
I-S, II-P, III-Q, IV-R done
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A crystalline solid:
A)
changes abruptly from solid to liquid when heated done
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B)
has no definite melting point done
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C)
undergoes deformation of its geometry easily done
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D)
has an irregular three-dimensional arrangements done
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E)
softens slowly done
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Select the right expression for determining packing fraction (PF) of \[NaCl\] unit cell (assume ideal), if ions along an edge diagonal are absent
A)
\[PF=\frac{\frac{4}{3}\pi \left( r_{+}^{3}+r_{-}^{3} \right)}{16\sqrt{2}r_{-}^{3}}\] done
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B)
\[PF=\frac{\frac{4}{3}\pi \left( \frac{5}{3}r_{+}^{3}+4r_{-}^{3} \right)}{16\sqrt{2}r_{-}^{3}}\] done
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C)
\[PF=\frac{\frac{4}{3}\pi \left( \frac{5}{2}r_{+}^{3}+r_{-}^{3} \right)}{16\sqrt{2}r_{-}^{3}}\] done
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D)
\[PF=\frac{\frac{4}{3}\pi \left( \frac{7}{2}r_{+}^{3}+r_{-}^{3} \right)}{16\sqrt{2}r_{-}^{3}}\] done
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