Chemistry - State of Matter Solid State
Exam Duration: 45 Mins Total Questions : 30
Which of the following is not characteristic of crystalline solids?
- (a)
They have a regular geometry
- (b)
They have sharp melting points
- (c)
They are isotropic
- (d)
They undergo a clean cleavage
Which of the following is not a crystalline solid?
- (a)
Naphthalene
- (b)
Benzoic acid
- (c)
Copper
- (d)
Fibre glass
Solid carbon dioxide is an example of
- (a)
metallic crystal
- (b)
cavalent crystal
- (c)
molecular crystal
- (d)
ionic crystal
An example of a substance possessing giant covalent structure is
- (a)
Solid \(CO_2\)
- (b)
silica
- (c)
iodine crystal
- (d)
white phosphorus
In face centred cubic cell, an atom at the face centre is shared by
- (a)
4 unit cells
- (b)
2 unit cells
- (c)
1 unit cell
- (d)
6 unit cells
A monoclinic crystal has dimensions
- (a)
\(a\neq b \neq c, \alpha = \gamma = 90^o; \beta\neq 90^o\)
- (b)
\(a= b = c, \alpha = \beta = \gamma = 90^o\)
- (c)
\(a= b = c, \alpha = \beta = 90^o; \gamma = 120^o\)
- (d)
\(a\neq b = c, \alpha = \beta = \gamma= 120^o\)
The ABAB... packing and ABCABC.... packing are respectively called as
- (a)
hep and ccp
- (b)
ccp and hcp
- (c)
bcc and hep
- (d)
hep and bcc
The coordination number of a cation occupying an octahedral hole is
- (a)
4
- (b)
6
- (c)
8
- (d)
12
At the limiting value of radius ratio \({r^+\over r^-},\)
- (a)
forces of attraction are larger than the forces of repulsion
- (b)
forces of attraction are smaller
- (c)
than the forces of repulsion
- (d)
None of the above
For an ionic crystal of the general formula AX and coordination number 6, the value of radius ratio will be
- (a)
greater than 0.73
- (b)
in between 0.73 and 0.41
- (c)
in between 0.14 and 0.22
- (d)
less than 0.22
The number of equidistance oppositely charged ions in sodium chloride crystal is
- (a)
2
- (b)
4
- (c)
6
- (d)
8
Lattice structure of group I element is
- (a)
fcc
- (b)
bcc
- (c)
hcp
- (d)
ccp
KCL crystallises in the same type of lattice as does NaCl. Given, \({r_{Na^+}\over r_{cl^-}}=0.5\) and \({r_{Na\ +}\over r_{K^+}}=0.7.\) Then ratio of the side of the unit cell for NaCl to that for KCl is
- (a)
1 : 1.172
- (b)
1 ; 1.143
- (c)
1 : 1.1413
- (d)
1 : 1.732
Calculate the wavelength of X-rays which produces a diffraction angle \(2\theta\) equal to \(16.80^o\) for a crystal. Assume first order diffraction with inter- particle distance in crystal of 0.2 nm.
- (a)
\(7.04\times 10^{-9}m\)
- (b)
\(5.84\times 10^{-11}\ m\)
- (c)
\(3.4\times 10^{-10}\ m\)
- (d)
\(5.84\times 10^{-9}\ m\)
Na and Mg crystallise in bcc and fcc crystals respectively, then the number of atoms of Na and Mg present in the unit cell of their respective crystal is
- (a)
4 and 2
- (b)
9 and 14
- (c)
14 and 9
- (d)
2 and 4
The anions (A) form hexagonal close packing and atoms (M) occupy only two-third of the octahedral voids. The general formula of the compound is
- (a)
\(M_2A_3\)
- (b)
MA
- (c)
\(MA_2\)
- (d)
\(M_3A_2\)
The NaCl structure can be converted into CsCl structure
- (a)
by application of high pressure
- (b)
by heating to 760 K
- (c)
both by heat and pressure
- (d)
the conversion is not possible
The number of atoms in 100g of an fcc crystal with density \(d = 10 g cm^{-3}\) and cell edge as 200 pm is equal to
- (a)
\(3\times 10^{25}\)
- (b)
\(0.5\times 10^{25}\)
- (c)
\(1\times 10^{25}\)
- (d)
\(2\times 10^{25}\)
The pykometric density of sodium chloride crystal is \(2.165\times 10^3\ kgm^{-3}.\) While its X-rays density is \(2.178\times 10^3\ kgm^{-3}\) The fraction of unoccupied sites in NaCl crystal is
- (a)
5.97
- (b)
\(5.97\times 10^{-2}\)
- (c)
\(5.97\times 10^{-1}\)
- (d)
\(5.97\times 10^{-3}\)
If 'a' stands for the edge length of the cubic systems simple cubic, body centred cubic and face centred cubic, then the ratio of radii of the spheres in these system will be respectively
- (a)
\({1\over 2}a:\sqrt3 a:{1\over \sqrt 2}a\)
- (b)
\({1\over 2}a:{\sqrt3\over 2}a:{\sqrt2\over 2}a\)
- (c)
\(1a:\sqrt3a:\sqrt2\ a\)
- (d)
\({1\over 2}a:{\sqrt3 \over 4}a:{1\over 2\sqrt 2}a\)
Calcium metal crystallises in fcc lattice with edge length 556 pm. Calculate the denstity (in g \(cm^{-3}\)) of metal if it contains 0.2% Schottky defects.
- (a)
3.992
- (b)
1.5455
- (c)
1.5427
- (d)
1.4987
If NaCl is doped with \(10^{-3}\) mol % \(SrCl_2,\) then concentration of cation vacancies will be
- (a)
\(1\times 10^{-3}\ mol\) %
- (b)
\(2\times 10^{-3}\ mol\) %
- (c)
\(3\times 10^{-3}\ mol\) %
- (d)
\(4\times 10^{-3}\ mol\) %
CsCl crystallises in body centred cubic lattice. If 'a' its edge length, then which of the following expressions is correct?
- (a)
\(r_{Cs}+r_{Cl^-}=3a\)
- (b)
\(r_{Cs}+r_{Cl^-}={3a\over 2}\)
- (c)
\(r_{Cs}+r_{Cl^-}={\sqrt3\over 2}a\)
- (d)
\(r_{Cs}+r_{Cl^-}=\sqrt3a\)
which of the following exists as covalent crystals in the solid state?
- (a)
Iodine
- (b)
Silicon
- (c)
Sulphur
- (d)
Phosphorus
Lithium forms body central cubic structure. The length of the side of its unit cell is 351 pm. Atomic radius of lithium will be
- (a)
175 pm
- (b)
300 pm
- (c)
240 pm
- (d)
152 pm
Copper crystallises in fcc lattice with a unit cell edge of 361 pm. The radius of copper atoms is
- (a)
181 pm
- (b)
108 pm
- (c)
128 pm
- (d)
157 pm
Percentage of fee space in cubic close - packed structure and in body-centred packed structure are respectively
- (a)
48% and 26%
- (b)
30% and 26%
- (c)
26% and 32%
- (d)
32% and 48%
In a compound, atoms of element Y form cubical - closest packing and those of elements X occupy 2/3 of tetrahedral voids. The formula of the compound will be
- (a)
\(X_3Y\)
- (b)
\(X_4Y_3\)
- (c)
\(X_2Y_3\)
- (d)
\(X_2Y\)
Total volume of atoms present in a face-centred cubic unit cell of a metal is (r is atomic radius)
- (a)
\(16\over 3\pi r^3\)
- (b)
\({20\over 3}\pi r^3\)
- (c)
\({24\over 3}\pi\ r^3\)
- (d)
\({12\over 3}\pi r^3\)
How many unit cells are present in a cube-shaped ideal crystal of NaCl mass 1.00 g?
- (a)
\(1.71\times 10^{21}\)
- (b)
\(2.57\times 10^{21}\)
- (c)
\(5.14\times 10^{21}\)
- (d)
\(1.28\times 10^{21}\)