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Published on: 23/08/2019
The Solid State
Download CBSE Class 12th Standard CBSE Chemistry question papers, sample papers, important questions, and previous year solved papers in PDF format. Get free study materials, NCERT solutions, and exam preparation resources for Class 12th Standard CBSE Chemistry
Questions + Answers key
Take MCQ Chemistry Test
1.
Name an element with which germanium can be doped to produce an n-type semiconductor.
2.
What is the maximum possible coordination number of an element ?
3.
Copper is conducting as such will copper sulphate is conducting only in molten state or in aqueous solution. Why
4.
What is the effect of Schottky and Frenkel defects on the crystaline solids?
5.
What makes the crystal of KCI appear sometimes violet?
6.
Name the crystal defect which lowers the density of an ionic crystal.
7.
Name an element with which silicon can be doped to give a p-type semiconductor.
8.
Name the non-stoichiometric point defect responsible for colour in alkali halides.
9.
What types of solids are electrical conductors, malleable and ductile?
10.
Why is glass considered as supercooled liquid?
11.
How many atoms can be assigned to its unit cell if an element forms
(i) a body-centred cubic cell, and
(ii) a face-centred cubic cell?
12.
A solid with cubic crystal is made of two elements 'P' and 'Q'. Atoms of 'Q' are at the corners of the cube and 'P' at body centre. What is formula of compound?
13.
Conductivity of silicon increases on doping it with phosphorus. Why
14.
What is the two dimensional coordination number of a molecule in square close-packed layer?
15.
A cubic solid is made of two elements X and Y. Atoms Y are at the corners of the cube and X at the body centre. What is the formula of the compound?
16.
In an ionic compound A+X-,the radii of A+ and X- ions are 1.0pm and 2.0pm respectively.The volume of the unit cell of the crystal AX will be
27pm3
64pm3
125pm3
216pm3
17.
A compound MpXq has cubic close packing(ccp) arrangement of X.Its unit cell structure is shown below.The empirical formula of the compound is
MX
MX2
M2X
M5X14
18.
The packing efficiency of the two-dimensional square unit cell shown below is
39.27%
68.02%
74.05%
78.54%
19.
The vacant space in bcc lattice unit cell is
23%
32%
26%
48%
20.
Which of the following statement about amorphous solids is incorrect?
They melt over a range of temperature
They are anisotropic
There is no orderly arrangement of particles
They are rigid and incompressible
21.
Which of the following exists as covalent crystals in the solid state?
Phosphorus
Iodine
Silicon
Sulphur
22.
In crystal structure of NaCl, total number of Cl- ions in a unit cell is
6
4
8
2
23.
The number of octahedral sites per sphere in fcc structure is
8
4
2
1
24.
In a tetragonal crystal
\(a=b=c,\alpha =\beta ={ 90 }^{ ° }\neq \gamma \)
\(\alpha =\beta =\gamma ={ 90 }^{ ° },a=b\neq c\)
\(\alpha =\beta =\gamma ={ 90 }^{ ° },a\neq b\neq c\)
\(\alpha =\beta ={ 90 }^{ ° }\gamma ={ 120 }^{ ° },a=b\neq c\)
25.
The property of crystalline solid is not
anisotropic
isotropic
hard
dense
1.
( )
Arsenic
2.
( )
12
3.
( )
Copper is a conductor because it has free electrons to move, where as CuSO4 conducts electricity in molten state because ions become free to move in molten state or in aqueous solution but not in solid state.
4.
( )
The density decreases in the case of Schottky defect, whereas it remain the same in the case of Frenkel defect.
5.
( )
It is due to presence of F-centre. Electrons present at the site of anion forming f-centre absorb ligh form visible region and radiate complementary colour.
6.
( )
Schottky defect.
7.
( )
Silicon doped with Gallium will be p-type semiconductor.
8.
( )
Metal excess defect: Excessof metal ions and formation of F-centre due to trapped electrons are responsible for colour in alkali halides.
9.
( )
Metallic solids are electrical conductors, malleable and ductile.
10.
( )
It is because glass windows are thicker at the bottom and thinner at the top. it shows that glass can flow, that is why it is called super cooled liquid.
11.
( )
(i) Z = 2 for bcc element
(ii) Z = 4 for fcc element
12.
( )
\(Q=8\times \frac { 1 }{ 8 } =1, \ P=1\)
\(\therefore\) Formula of compound is PQ.
13.
( )
It is because it forms n-type semiconductor in which electrons are free to move.
14.
Four
15.
Y = 8 ×\(\frac{1}{8}\)= 1; X = 1,
∴ Formula is XY.
16.
(d)
216pm3
17.
MX2
18.
78.5%
19.
(b)
32%
20.
(b)
They are anisotropic
21.
(c)
Silicon
22.
(b)
4
23.
(d)
1
24.
(b)
\(\alpha =\beta =\gamma ={ 90 }^{ ° },a=b\neq c\)
25.
(b)
isotropic
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