QUESTION
BANK
CLASS
XII
UNIT
1: SOLID STATE
ONE MARK QUESTIONS
|
Q.No.
|
QUESTION
|
|
1
|
How
many unit cells constitute one unit cell of a face centered cubic crystal?
|
|
2
|
What
type of semiconductor is obtained when silicon is doped with boron?
|
|
3
|
What
type of magnetism is shown in the following alignment of magnetic moments?
↓↓↓↓↓↓↓↓↓↓
|
|
4
|
What
type of stoichiometric defect is shown by AgCl?
|
|
5
|
What
type of substances would make better permanent magnets: Ferromagnetic or
Ferrimagnetic?
|
|
6
|
Why
does presence of excess lithium make LiCl crystals pink?
|
|
7
|
A
solid with cubic crystal is made of two elements P & Q. atoms of Q are at
the corners of the cube and P at the centre. What is the formula of the
compound?
|
|
8
|
What
change occurs when AgCl is doped with CdCl2?
|
|
9
|
Calculate
the number of atoms in a face centred cubic unit cell.
|
|
10
|
Which
type ionic substance show Schottky defect in solids?
|
|
11
|
What
is meant by “doping” in a semiconductor?
|
|
12
|
Write
the point of distinction between metallic solid and ionic solid other than
metallic lusture.
|
|
13
|
How
may the conductivity of an intrinsic semiconductor be increased?
|
|
14
|
What
type of stoichiometric defect is shown by AgBr and AgI?
|
|
15
|
Some
of the glass objects recovered from ancient monuments look milky instead of
being transparent. Why?
|
|
16
|
What
type of defect arises when a solid is heated?
|
|
17
|
What
is intrinsic semiconductors? Give one example
|
|
18
|
Why
does LiCl acquire pink colour when heated in Li vapours?
|
|
19
|
Crystalline
solids are “anisotropic in nature”. What does this statement mean?
|
|
20
|
Which
stoichiometric defect in crystals increases the density of a solid?
|
|
21
|
What
is the total number of atoms per unit cell in a face –centred (fcc) cubic structure?
|
|
22
|
What
is the coordination number of each ion in a rock salt type structure?
|
|
23
|
Which
point defect in a crystal does not alter the density of the relevant solid?
|
|
24
|
Which
point defect in a crystals alters the density of the solid?
|
|
25
|
Which
point defect decreases the density of a solid?
|
|
26
|
How
do metallic & ionic substances differ in conducting electricity?
|
|
27
|
What
type of interactions hold together the molecules in a polar molecular solid?
|
|
28
|
What
type of semiconductor is obtained when silicon is doped with arsenic?
|
|
29
|
Give
one example of ionic compound which shows Frenkel Defect.
|
|
30
|
Why glass is
considered a super cooled
liquid?
|
|
31
|
Solid A is a very hard
electrical insulator in solid as well as in molten
state and melts at extremely high temperature. What type of solid is it?
|
|
32
|
A compound is formed by two elements X and Y. Atoms
of the element Y (as anions) make ccp and
those of the element X (as cations)
occupy all the octahedral voids. What is the formula
of the compound?
|
|
33
|
Atoms of
element B form hcp lattice and those of the element A occupy
2/3rd of tetrahedral voids. What is the formula of the compound formed
by the elements A and B?
|
|
34
|
A compound
is formed by two elements M and N. The element
N forms ccp and atoms of M occupy 1/3rd of tetrahedral voids. What
is
the formula of the compound?
|
|
|
Ferric oxide crystallises in a hexagonal close-packed array of oxide
ions
with two out
of every
three octahedral
holes occupied
by ferric
ions. Derive the formula of the ferric
oxide.
|
|
|
|
2 MARKS
QUESTIONS
|
Q.No.
|
QUESTION
|
|
1
|
Account
for the following-
a.
Schottky defects lower the density of the related
solid.
b.
Conductivity of silicon increases on doping it with
phosphorous.
|
|
2
|
Aluminium
crystallises in an fcc structure. Atomic radius of the metal is 125pm. What
is the length of the side of the unit cell of the metal?
|
|
3
|
If
NaCl is doped with 10-3mole% SrCl2, what will be the
concentration of cationic vacancies (NA=6.02x1023)?
|
|
4
|
What
is semiconductor? Describe two main types of semiconductors and contrast
their mechanism.
|
|
5
|
A
compound is forms hcp structure. What is the total number of voids in 0.5mol
of it? How many of these are tetrahedral voids?
|
|
6
|
The
unit cell of an element of atomic mass 108u and density 10.5gcm-3 is a cube
with edge length 409pm. Find the type of unit cell of the crystal.
(Given:
Avogadro’s number NA= 6.02x1023mol-1)
|
|
7
|
a.
|
|
8
|
An
element of X crystallises in fcc structure. 208g of it has 4.2832x1024
atoms. Calculate the edge of the unit cell, if density of X is 7.2gcm-3.
|
|
9
|
Calculate
the packing efficiency of a metal crystal for a simple cubic lattice.
|
|
10
|
Explain
the following terms with suitable example:
a.
Anti-ferromagnetism
b.
13-14 compounds
|
|
11
|
An
alloy of gold and cadmium crystallises with a cubic structure in which gold
atoms occupy the corners and cadmium atoms fit into the face centres. Assign
formula for this alloy.
|
|
12
|
In
terms of band theory, explain the differences between a conductor and a
semiconductor and give one suitable example for each.
|
|
13
|
Calculate
the packing efficiency of a ccp structure.
|
|
14
|
Explain
the following terms with suitable example:
i.
Schottky defect
ii.
Interstitial defect
|
|
15
|
Chromium
metal crystallises in a body centred cubic lattice. The length of the unit
cell edge is found to be 287pm. Calculate the atomic radius of chromium.
|
|
16
|
The
edge of face centred cubic unit cell of calcium is 556.5pm. Calculate the radius of calcium atom.
|
|
17
|
What
type of stoichiometric defect is shown by –
i.ZnS
ii.AgBr
|
|
18
|
What makes a glass
different from a solid such as quartz?
Under what conditions quartz could be converted into glass
|
|
19
|
If the radius of the octahedral void is r and radius
of the atoms
in close- packing is R, derive
relation between r and R.
|
|
20
|
Analysis shows that nickel oxide
has the formula Ni0.98O1.00.
What fractions of Ni exist as Ni2+
and Ni3+.
|
3MARKS QUESTIONS
|
Q.No.
|
QUESTION
|
|
1
|
Iron
(II) oxide has a cubic structure and each unit cell has a size of 5A0.
If density of this oxide is 4gmcm-3, calculate the number of Fe2+
and O2- ions present in each unit cell.
|
|
2
|
Niobium
crystallises in body centred cubic structure. If density is 8.55gcm-3,
calculate atomic radius of niobium, given its atomic mass 93u.
|
|
3
|
An
element crystallises in a structure having fcc unit cell of edge 200pm.
Calculate the density if 200g of this element contains 24x1023
atoms.
|
|
4
|
Tungsten
crystallises in body centred cubic unit cell. If the edge of the unit cell is
316.5pm, what is the radius of tungsten atom?
|
|
5
|
Iron
has body centred cubic unit cell with a cell dimension of 286.65pm. The
density of iron is 7.874gcm-3. Use this information to calculate
Avogadro’s number.
(At.
Mass of Fe = 55.845u)
|
|
6
|
Copper
crystallises with face centred cubic unit cell. If the radius of copper atom
is 127.8pm, calculate the density of copper metal.
(At.
Mass of Cu= 63.55u & Avogadro’s number NA= 6.02x1023mol-1)
|
|
7
|
What
is the distance between Na+ & Cl- ions in NaCl
crystal if its density is 2.165gcm-3?
(At.
Mass of Na=23u, Cl=35.5u, Avogadro’s number NA= 6.02x1023mol-1)
|
|
8
|
Silver
crystallises in face centred cubic unit cell. Each side of this unit cell has
a length 409pm. Calculate the radius of the silver atom. (Assume that each
face atom is touching the four corner atoms )
|
|
9
|
How
will you account for the following:
i.
Frenkel defects are not found in alkali metal
halides
ii.
Schottky defect lowers the density of related solids
iii.
Impurity doped silicon is a semiconductor.
|
|
10
|
Explain
the following terms with suitable example:
a.
Ferromagnetism
b.
Ferrimagnetism
c.
Paramagnetism
|
|
11
|
Silver
crystallises in a fcc lattice. The edge length of its unit cell is 4.077x10-8cm
and its density is 10.5gcm-3. Calculate the atomic mass of silver.
(NA=
6.02x1023mol-1)
|
|
12
|
The
well-known mineral fluorite is chemically calcium fluoride. It is known that
in one unit cell of this mineral there are 4 Ca2+ ions and 8F-
ions and that Ca2+ ions are arranged in a fcc lattice. The F- ions
fill all the tetrahedral holes in the face centred cubic lattice of Ca2+
ions. The edge of the unit cell is 5.46x10-8cm in length. The
density of the solid is 3.18g cm-3. Use this information to calculate
Avogadro’s number (Molar mass of CaF2 = 78.08g mol-1)
|
|
13
|
Explain
the following terms with suitable example:
i.
Doping
ii.
12-16
Compounds
iii.
F-center
|
No comments:
Post a Comment