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TN 12th Computer Applications வலையமைப்பு வடமிடல் Sample Question Papers Study Material - QB365 Set A
Published on: 28/11/2025
Download Tamil Nadu 12th Standard Chemistry question papers, model tests, one-mark questions, important questions, and public exam papers in PDF format. Free study materials and answer keys for TN State Board students.
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1.
The number of unit cells in 58.5 g of NaCl is nearly _______.
0.5 x 1024
1.5 x 1023
3 x 1022
6 x 1026
2.
The general formula of an ionic compound which crystallises in body-centred cubic structure is _______.
AB
AB2
A2B
AB3
3.
What types of waves are suitable for diffraction studies of crystals?
\(\alpha\)-rays
\(\beta\)-rays
X-rays
\(\gamma\)-rays
4.
What is the arrangement of layers in a cubic close packing of spheres?
ABABAB....
ABCABCABC...
AAAAA...
None of these
5.
The number of chloride ions that surrounds the central Na+ ion in NaCl crystal is _______.
12
8
6
4
6.
The number of close packed spheres is 'n'. The number of tetrahedral voids generated is equal to _______.
n
2n
2n2
3n
7.
The arrangement of crystallographic axes and angles respectively in hexagonal crystal systems is _______.
\(\mathrm{a} \neq \mathrm{b} \neq \mathrm{c} ; \alpha=\beta=\gamma=90^{\circ}\)
\(\mathrm{a}=\mathrm{b} \neq \mathrm{c} ; \alpha=\beta=\gamma=90^{\circ}\)
\(\mathrm{a}=\mathrm{b} \neq \mathrm{c} ; \alpha=\beta=90^{\circ}, \gamma=120^{\circ}\)
\(a=b=c ; a \neq \beta \neq \gamma=90^{\circ}\)
8.
In FCC unit cell of the edge length is \(8 \sqrt{2}\) pm. The radius of the metal atom is ________ Å.
0.04
0.02
8 x 10-2
\(\frac{8}{\sqrt{2}}\)
9.
The packing efficiency of a face centered cubic structure is _______.
74%
68%
52.38%
48%
10.
A two dimensional solid pattern formed by two different atoms X and Y is shown below. The black and white squares represent atoms X and Y respectively. The simplest formula for the compound based on the unit cell from the pattern is _______.
XY8
X4Y9
XY2
XY4
11.
The crystal with a metal deficiency defect is ________.
NaCl
FeO
ZnO
KCl
12.
The cation leaves its normal position in the crystal and moves to some interstitial position, the defect in the crystal is known as _____.
Schottky defect
F center
Frenkel defect
non-stoichiometric defect
13.
Schottky defect in a crystal is observed when ______.
unequal number of anions and anions are missing from the lattice
Equal number of cations and anions are missing from the lattice
an ion leaves its normal site and occupies an interstitial site
no ion is missing from its lattice
14.
Potassium has a bcc structure with nearest neighbor distance 4.52 \(\overset{o}{A}\). Its atomic weight is 39. its density will be_______.
915 kg m-3
2142 kg m-3
452 kg m-3
390 kg m-3
15.
If ‘a’ is the length of the side of the cube, the distance between the body centered atom and one corner atom in the cube will be_________.
\(\left( \cfrac { 2 }{ \sqrt { 3 } } \right) a\)
\(\left( \cfrac { 4 }{ \sqrt { 3 } } \right) a\)
\(\left( \cfrac { \sqrt { 3 } }{ 4 } \right) a\)
\(\left( \cfrac { \sqrt { 3 } }{ 2 } \right) a\)
16.
If ‘a’ stands for the edge length of the cubic system sc, bcc, and fcc. Then the ratio of radii of spheres in these systems will be respectively ________.
\(\left( \frac { 1 }{ 2 } a;\frac { \sqrt { 3 } }{ 2 } a;\frac { \sqrt { 2 } }{ 2 } a \right) \)
\(\left( \sqrt { 1a } :\sqrt { 3a } :\sqrt { 2a } \right) \)
\(\left( \frac { 1 }{ 2 } a:\frac { \sqrt { 3 } }{ 4 } a:\frac { 1 }{ 2\sqrt { 2 } } a \right) \)
\(\frac { 1 }{ 2 } a:\sqrt { 3 } a:\frac { 1 }{ \sqrt { 2 } } a\)
17.
The yellow colour in NaCl crystal is due to ________.
excitation of electrons in F centers
reflection of light from Cl- ion on the surface
refraction of light from Na+ ion
all of the above
18.
The fraction of total volume occupied by the atoms in a simple cubic is ________.
\(\left( \frac { \pi }{ 4\sqrt { 2 } } \right) \)
\(\left( \frac { \pi }{ 6 } \right) \)
\(\left( \frac { \pi }{ 4 } \right) \)
\(\left( \frac { \pi }{ 3\sqrt { 2 } } \right) \)
19.
The radius of an atom is 300pm, if it crystallizes in a face centered cubic lattice, the length of the edge of the unit cell is ________.
488.5pm
848.5pm
884.5pm
484.5pm
20.
The vacant space in bcc lattice unit cell is ________.
48%
23%
32%
26%
21.
A solid compound XY has NaCl structure if the radius of the cation is 100pm, the radius of the anion will be ________.
\(\left( \frac { 100 }{ 0.414 } \right) \)
\(\left( \frac { 0.732 }{ 100 } \right) \)
100 x 0.414
\(\left( \frac { 0.414 }{ 100 } \right) \)
22.
CsCl has bcc arrangement, its unit cell edge length is 400pm, its inter atomic distance is ________.
400pm
800pm
\(\sqrt { 3 } \times 100pm\)
\(\left( \frac { \sqrt { 3 } }{ 2 } \right) \times 400pm\)
23.
The ionic radii of A+ and B− are 0.98 x 10-10 m and 1.81 x 10-10 m. the coordination number of each ion in AB is ________.
8
2
6
4
24.
In a solid atom M occupies ccp lattice and \(\left( \frac { 1 }{ 3 } \right) \) of tetrahedral voids are occupied by atom N. Find the formula of solid formed by M and N ________.
MN
M3N
MN3
M3N2
25.
The number of unit cells in 8 gm of an element X (atomic mass 40) which crystallizes in bcc pattern is (NA is the Avogadro number)________.
6.023 x 1023
6.023 x 1022
60.23 x 1023
\(\left( \frac { 6.023\times { 10 }^{ 23 } }{ 8\times 40 } \right) \)
26.
27.
Solid CO2 is an example of ________.
Covalent solid
metallic solid
molecular solid
ionic solid
28.
The ratio of close packed atoms to tetrahedral hole in cubic packing is ________.
1:1
1:2
2:1
1:4
29.
An ionic compound Ax By crystallizes in fcc type crystal structure with B ions at the centre of each face and A ion occupying corners of the cube the correct formula of Ax, By is ________.
AB
AB3
A3B
A8B6
30.
Graphite and diamond are ________.
Covalent and molecular crystals
ionic and covalent crystals
both covalent crystals
both molecular crystals
1.
(b)
1.5 x 1023
2.
(a)
AB
3.
(c)
X-rays
4.
(b)
ABCABCABC...
5.
(c)
6
6.
(b)
2n
7.
(c)
\(\mathrm{a}=\mathrm{b} \neq \mathrm{c} ; \alpha=\beta=90^{\circ}, \gamma=120^{\circ}\)
8.
(a)
0.04
9.
(a)
74%
10.
(a)
XY8
11.
(b)
FeO
12.
(c)
Frenkel defect
13.
(b)
Equal number of cations and anions are missing from the lattice
14.
\(\rho=\frac{\mathrm{n} \times \mathrm{M}}{\mathrm{a}^{3} \mathrm{~N}_{\mathrm{A}}}\)
For bcc n =2, M = 39 nearest distance 2r = 4.52 A0
\(a =\frac{4r}{\sqrt {3}} = \frac { 2\times 4.52 \times 10^{-10} }{ \sqrt{3}} \)
\(\rho =\frac { {( 5.21\times 10^{-10})^{ 3 }} \times (6.023 \times 10^{-23}) }{ 2 \times 39} \)
ρ = 915 kgm-3
15.
If a is the length of the side, then the length of the leading diagonal passing through the body centered atom is \(\sqrt{3a} \)
Required distance = \(\left( \cfrac { \sqrt { 3 } }{ 2 } \right) a\)
16.
sc ⇒ 2r = a
⇒ r = a/2
bcc ⇒ 4r = \( \sqrt{3a} \) ⇒ r = \(\frac { \sqrt{3a}} {4}\)
fcc ⇒ 4r ⇒ \( \sqrt{2a} \) ⇒ r = \(\frac { \sqrt{2a}} {4} = \frac { a} {2\sqrt{2a}}\)
\(\left( \frac { a }{ 2 } :\frac { \sqrt { 3 } }{ 4 } a:\frac { a }{ 2\sqrt { 2 } } \right) \)
17.
(a)
excitation of electrons in F centers
18.
(b)
\(\left( \frac { \pi }{ 6 } \right) \)
19.
let edge length = a
\(\sqrt{2a} = 4r\)
\(a = \frac{4 \times 300}{\sqrt {2}}\)
a = 600 x 1.414
a = 848.4 pm
20.
Packing efficiency = 68%
\(\therefore\)empty space percentage = 100 - 68 = 32%
21.
For a fcc structure = rx+ / ry- = 0.414
Given that rx+ = 100 pm
ry = 100pm/0.414
22.
\(3 \sqrt{a} = r_{C_{s+}} + 2r_{C_{f-}} + r_{C_{s+}} \)
\(\left( \frac { \sqrt { 3 } }{ 2 } \right) a = r_{C_{s+}} + r_{C_{f-}} \)
\(\left( \frac { \sqrt { 3 } }{ 2 } \right) \times 400\)= inter ionic distance
23.
\(\left( \frac { r_{c^+} }{ r_{A^-} } \right) \) = \(\left( \frac { 0.98 \times 10^{-10 }}{ 1.81 \times 10^{-10} } \right) = 0.54\)
It is in the range of 0.414 to 0.732, hence the coordination number of each ion is 6.
24.
If the total number of M atoms is n, then the number of tetrahedral voids = 2n
Given that \(\left( \frac { 1 }{ 3 } \right) ^{rd}\) of tetrahedral voids are occupied.
i.,e \(\left( \frac { 1 }{ 3 } \right) \times 2n\) are occupied by N atoms
\(\therefore\)M : N = n : \(\left( \frac { 2 }{ 3 } \right) n\)
= 1 : \(\frac { 2 }{ 3 }\)
Hence M3N2 = 3 : 2
25.
In bcc unit cell,
2 atoms = 1 unit cell
Number of atoms in 8 g of element is, Number of moles = 8g / 40 g mol-1 = 0.2 mol
1 mole contains 6.023 x1023 atoms
0.2 mole contains 0.2 x 6.023 x 1023 atoms
[1 unit cell / 2 atoms] x 0.2 x 6.023 x 1023
= 6.023 x 1022 unit cells.
26.
(c)
27.
Lattice points are occupied by CO2 molecules
28.
If number of close packed atoms = N, then
The number of Tetrahedral holes formed = 2N
The number of Octahedral holes formed = N
Therefore, N:2N = 1:2
29.
Number of A ions = Nc/8 = 8/8 = 1
Number of B ions = Nf/2 = 6/2 = 3
Simplest formula = AB3
30.
(c)
both covalent crystals
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