Q.1.
A mineral is made of calcium, titanium and oxygen, Ca2+ ions located at corners, Ti4+ ions are at the bodycentre and O2- ions at face-centre of the unit cell, The molecular formula of the mineral is ..
-
20%
a) CaTiO2
-
40%
b) CaTi2O3
-
40%
c) CaTiO3
-
0%
d) XaTi2O4
Q.2.
AB crystallises in body-centred cubic lattice with edge length 387pm. Distance between oppositely charged ions will be ..[ BHU 2009]
-
25%
a) 200 pm
-
0%
b) 250 pm
-
25%
c) 300 pm
-
50%
d) 335 pm
Explanation
Q.3.
8:8 coordination of CsCl is found to change into 6:6 coordination
-
20%
a) on increasing the pressure
-
20%
b) on increasing the temperature
-
20%
c) on decreasing the pressure
-
40%
d) on decreasing the temperature
Q.4.
Fe3O4 is ferrimagnetic at room temperature but at 850K, it becomes
-
20%
a) paramagnetic
-
20%
b) diamagnetic
-
60%
c) ferromagnetic
-
0%
d) non-magnetic
Q.5.
The number of atoms contained in one face-centred cubic unit cell of mono-atomic substance is
-
25%
a) 1
-
50%
b) 2
-
25%
c) 3
-
0%
d) 4
Q.6.
Schottky defects occur mainly in electrovalent compounds where
-
25%
a) positive ions and negative ions are of different size
-
0%
b) positive ions and negative ions are of same size
-
50%
c) positive ions are small and negative ions are big
-
25%
d) positive ions are big and negative ions are small
Q.7.
In Schottky defect ...
-
25%
a) Some of lattice sites are vacant
-
50%
b) an ion occupies interstitial position between lattice points
-
25%
c) a lattice site is occupied by electron
-
0%
d) the radius ratio r+/r-, is low
Q.8.
The inter ionic distance for cesium chloride crystal will be
-
0%
a) a
-
75%
b) a/2
-
25%
c) a(√3/2)
-
0%
d) 2a√3
Q.9.
In an NaCl crystal, each chloride ion is surrounded by ...
-
50%
a) 6 sodium ions
-
0%
b) 6 chloride ions
-
25%
c) 8 sodium ions
-
25%
d) 4 sodium ions
Q.10.
Amorphous solids may be considered as ...
-
0%
a) molecular solids
-
25%
b) supercooled solids
-
50%
c) supercooled liquids
-
25%
d) covalnet network solids
Q.11.
The anions (A) form hexagonal closed packing and atoms (M) occupy only two-third of octahedral voids in it; the general formula of the compound is ...
-
0%
a) MA
-
0%
b) A2
-
100%
c) M2A3
-
0%
d) M3A2
Q.12.
First three nearest neighbor distance for primitive cubic unit cell will be ( edge length of unit cell = l)
-
0%
a) l, l√2, 2l
-
50%
b) l, l√2, l
-
50%
c) l, l√2, l√3
-
0%
d) l√3, l√2, l
Explanation
Q.13.
Close packing is maximum in the crystal lattice of
-
25%
a) face-centred cubic
-
0%
b) body-centred cubic
-
25%
c) simple-centred cubic
-
50%
d) none of these
Q.14.
The unit cell of a binary compound of A and B metals has a ccp structure with A atoms occupying the corners and B atoms occupying the centres of each faces of the cubic unit cell. If during the crystallisation of this alloy, in the unit cell two A atoms are missed, the overall composition per unit cell is ...
-
50%
a) A6B24
-
50%
b) AB4
-
0%
c) AB6
-
0%
d) AB8
Q.15.
Which defect causes decrease in the density of a crystal?
-
0%
a) Schottky
-
25%
b) Frenkel
-
75%
c) F-centre
-
0%
d) Interstitial
Q.16.
The coordination number of a metal crystallizing in hexagonal close packing structure is
-
0%
a) 4
-
0%
b) 6
-
50%
c) 8
-
50%
d) 12
Explanation
Q.17.
The closest-packing sequence ABC ABC ... represents
-
0%
a) primitive cubic packing
-
0%
b) body-centred cubic packing
-
67%
c) face-centred cubic packing
-
33%
d) hexagonal packing
Q.18.
A metallic crystal crystallizes into a lattice containing a sequence of layers AB AB AB. A packing of sphere leaves out voids in the lattice. What is the percentage of volume of this lattice in empty space?
-
25%
a) 26%
-
25%
b) 50%
-
25%
c) 74%
-
25%
d) None of these
Q.19.
he number of crystal system known are ...
-
25%
a) 4
-
0%
b) 6
-
50%
c) 7
-
25%
d) 8
Q.20.
In closed packed array of N spheres, the octahedral holes are
-
0%
a) N/2
-
25%
b) N
-
50%
c) 2N
-
25%
d) 4N
Q.21.
A crystal lattice with alternate +ve and -ve ions has radius ratio 0.524, its coordination number is ...[ PMT 2002]
-
0%
a) 3
-
75%
b) 4
-
25%
c) 6
-
0%
d) 12
Q.22.
If we mix a pentavalent impurity in a crystal lattice of germanium, what type of semiconductor formation will occur? ..[ CBSE 1996]
-
25%
a) p-type semiconductor
-
25%
b) n-type semiconductor
-
50%
c) both types
-
0%
d) none of these
Q.23.
A metal crystallised with a body-centred cubic lattice. The edge of the unit cell is 240√3 pm. The diameter of the metal atom ion is ..[ AIPMT 2012]
-
0%
a) 180 pm
-
50%
b) 360 pm
-
50%
c) 288 pm
-
0%
d) 408 pm
Explanation
Q.24.
In a solid lattice, the cation has left a lattice site and is located at an interstitial position. the lattice defect is ...[ BHU 2008]
-
33%
a) Interstitial defect
-
0%
b) Vacancy defect
-
67%
c) Frenkel defect
-
0%
d) Schottky defect
Q.25.
The packing fraction of the element that crystallises in Body -centred cubic unit cell arrangement is
-
25%
a) π/6
-
0%
b) π/2
-
50%
c) π/4
-
25%
d) π/3
Explanation
Q.26.
Tetragonal crystal system has the following unit cell dimensions ...[MPPMT 1993]
-
0%
a) a=b=c and α=β=γ=90°
-
50%
b) a=b≠c and α=β=γ=90°
-
25%
c) a≠b≠c and α=β=γ=90°
-
25%
d) a=b≠c and α=β=90°, γ=120°
Q.27.
How many unit cells are there in 1 g of NaCl?
-
25%
a) 6.023×1023
-
0%
b) 2.57×1021
-
25%
c) 2×6.023×1023
-
50%
d) 4×6.023×1023
Explanation
Q.28.
In unit cell of NaCl lattice, there are ..
-
25%
a) 3Na+ ions
-
25%
b) 4NaCl units
-
25%
c) 6Na+ ions
-
25%
d) 6Cl- ions
Q.29.
In hexagonal close packed (hcp) structure of spheres, the fraction of the volume occupied by the sphere is A. In a cubic closed packed structure, the fraction of the volume occupied is B. The relation between A and B is
-
0%
a) A = B
-
25%
b) A > B
-
50%
c) A < B
-
25%
d) both cannot be compared
Q.30.
Which of following network solid is an exceptionally good conductor of electricity?
-
0%
a) Si
-
50%
b) SiC
-
0%
c) Graphite
-
50%
d) SiO2