Graphite and diamond are ________.

(a)

Covalent and molecular crystals

(b)

ionic and covalent crystals

(c)

both covalent crystals

(d)

both molecular crystals

The ratio of close packed atoms to tetrahedral hole in cubic packing is ________.

(a)

1:1

(b)

1:2

(c)

2:1

(d)

1:4

Assertion: monoclinic sulphur is an example of monoclinic crystal system
Reason: for a monoclinic system, \(a\neq b\neq c\) and \(\alpha =\gamma ={ 90 }^{ 0 },\beta \neq { 90 }^{ 0 }\) 
Codes:
a) Both assertion and reason are true and reason is the correct explanation of assertion
b) Both assertion and reason are true but reason is not the correct explanation of assertion.
c) Assertion is true but reason is false.
d) Both assertion and reason are false.

(a)

Both assertion and reason are true and reason is the correct explanation of assertion

(b)

Both assertion and reason are true but reason is not the correct explanation of assertion.

(c)

Assertion is true but reason is false.

(d)

Both assertion and reason are false.

The number of unit cells in 8 gm of an element X (atomic mass 40) which crystallizes in bcc pattern is (N_A is the Avogadro number)________.

(a)

6.023 x 10²³

(b)

6.023 x 10²²

(c)

60.23 x 10²³

(d)

\(\left( \frac { 6.023\times { 10 }^{ 23 } }{ 8\times 40 } \right) \)

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 ________.

(a)

MN

(b)

M₃N

(c)

MN₃

(d)

M₃N₂

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 ________.

(a)

8

(b)

2

(c)

6

(d)

4

A solid compound XY has NaCl structure if the radius of the cation is 100pm, the radius of the anion will be ________.

(a)

\(\left( \frac { 100 }{ 0.414 } \right) \)

(b)

\(\left( \frac { 0.732 }{ 100 } \right) \)

(c)

100 x 0.414

(d)

\(\left( \frac { 0.414 }{ 100 } \right) \)

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 ________.

(a)

488.5pm

(b)

848.5pm

(c)

884.5pm

(d)

484.5pm

The yellow colour in NaCl crystal is due to ________.

(a)

excitation of electrons in F centers

(b)

reflection of light from Cl^- ion on the surface

(c)

refraction of light from Na⁺ ion

(d)

all of the above

Schottky defect in a crystal is observed when ______.

(a)

unequal number of anions and anions are missing from the lattice

(b)

Equal number of cations and anions are missing from the lattice

(c)

an ion leaves its normal site and occupies an interstitial site

(d)

no ion is missing from its lattice

Which of the following defects decreases the density of the crystal?

(a)

Interstitial defect

(b)

Vacancy defect

(c)

Frankel defect

(d)

None of these above

A solid with formula ABC₃ would probably have, _______.

(a)

A at body centre, B at face centres and C at corners of the cube

(b)

A at corners of cube, B at body centre, C at face centre

(c)

A at corners of hexagon, B at centres of the hexagon and C inside the hexagonal unit cell

(d)

A at corner, B at face centre, C at body centre

Which of the following statement is correct?

(a)

On increasing temperature, the coordination number of solid remains unchanged.

(b)

On increasing pressure, the co-ordination number of solid increases.

(c)

On increasing pressure, the co-ordination number of solid decreases.

(d)

On increasing temperature, the coordination number of solid increases

In a body centred cubic unit cell, a metal atom at the centre of the cell is surrounded by how many other metal atoms?

(a)

12

(b)

4

(c)

6

(d)

8

A regular three dimensional arrangement of identical points in space is called _______.

(a)

Unit cell

(b)

Space lattice

(c)

Primitive

(d)

Crystallography

In the Bragg's equation for diffraction of X-rays, 'n' represents _______.

(a)

The number of moles

(b)

Avogadro number

(c)

A quantum number

(d)

Order of reflection

In a simple cubic cell, each point on a corner is shared by _______.

(a)

One unit cell

(b)

Two unit cell

(c)

8 unit cell

(d)

4 unit cell

The wavelength of X-ray is in the order of _______.

(a)

10^-8 cm

(b)

10^-10 c

(c)

10^-8 m

(d)

10^-10 nm

Crystalline solids are also called as _______.

(a)

supercooled liquids

(b)

true solids

(c)

pseudo solids

(d)

all the above

The defect arising due to an ion occupying interstitial position is called _______.

(a)

Schottky defect

(b)

Metal excess defect

(c)

Frenkel defect

(d)

Metal deficiency defect