MCQ Questions for Class 12 Engineering Chemistry The Solid State Quiz 11

In a solid, atom

$M$ occupy ccp lattice and

$1/3^{rd}$ of tetrahedral voids are occupied by atom

$N$ . Find formula of solid formed by

$M$ and

$N$ :-

0%
$M_3N_2$
0%
$M_2N_3$
0%
$M_4N_3$
0%
$M_3N_4$

Which is/are amorphous solid(s)?

0%
$NaCl$
0%
$CaF_2$
0%
Glass
0%
Plastic

Explanation

Amorphous solid is a solid that lacks a long range order and is characteristics of a crystal. Glass is a amorphous solid that exhibits a glass transition. NaCl is also another example of amorphous solids.

Amorphous materials have an internal structure mode of interconnected structure blocks.

Hence, the correct options are

$A$ and

$C$

$NH_3$ and

$BF_3$ form an adduct readily because they form

0%
a coordinate bond
0%
a hydrogen bond
0%
an ionic bond
0%
None of these

In an atomic bcc lattic what fraction of edge is not covered by atoms?

0%
032
0%
0.16
0%
0.134
0%
0.268

Explanation

Edge not covered by atom

$= a - 2r$
also in bcc,

$4r = \sqrt{3}a$
Therefore, edge not covered

$= a - \dfrac{\sqrt 3}{2}a = a \left ( \dfrac{2 - \sqrt 3}{2} \right )$

$\Rightarrow$ Fraction of edge not covered by atoms

$= \dfrac{2 - \sqrt{3}}{2} = 0.134$

In an ionic compound

$A^{+}X^{-}$ , the radii of

$A^{+}$ and

$X^{-}$ ions are 1.0 pm and 2.0pm, respectively. The volume of the unit cell of the crystal AX will be :

0%
$27\ pm^{3}$
0%
$64\ pm^{3}$
0%
$125\ pm^{3}$
0%
$216\ pm^{3}$

An element

$X$ (atomic mass

$= 24 gm/mol$ ) forms a face centered cubic lattice. If the edge length of the lattice is

$4$ x

$10^{-8}$

$cm$ and the observed density is

$2.40$ x

$10^{3}$

$kgm^{3}$ then the percentage occupancy of lattice points by element

$X$ is : (Use

$N_{A}$

$=$

$6$ x

$10^{23}$ )

0%
$96$
0%
$98$
0%
$99.9$
0%
None of the above

Explanation

Theoretical density

$= \dfrac{Z.M}{N_{A} . a^3}$

$= \dfrac{4 \times 24 \times 10^{-3}}{6 \times 10^{23} \times (4 \times 10^{-10})^{3}}$

$= 2.5 \times 10^{3} \,kg / m^{3}$

$\% \,occupancy = \dfrac{Observed \,density}{Ideal \,density} \times 100$

$= \dfrac{2.4 \times 10^{3}}{2.5 \times 10^{3}} \times 100 = 96\%$

The density of nickel (face centered cubic cell) is

$8.94\ g/cm^3$ at

$20^oC$ . What is the radius of the atom? (Atomic weight:

$Ni=59$ )

0%
$0.124 \ nm$
0%
$0.136 \ nm$
0%
$0.149 \ nm$
0%
$0.110 \ pm$

How many lithium atoms are present in a unit cell with edge length

$3.5\mathring { A }$ and density

$\quad 0.53gcm^{ -3 }$ ? (Atomic mass of Li =6.94)

0%
2
0%
1
0%
4
0%
6

Packing efficiency of hcp structure is _________.

0%
$68\%$
0%
$52.4\%$
0%
$74\%$
0%
$82\%$

In NaCI unit cell if all the ions lying along the axis as shown in the figure are removed. the number of

${ Na }^{ + }$ and

${ CI }^{ - }$ remaining in the unit cell are.

0%
4 and 4
0%
3 and 3
0%
1 and 1
0%
4 and 3

The number of carbon atoms in the unit cell of diamond is ___

0%
6
0%
1
0%
4
0%
8

The atom that present in the centre of BCC unit cell share with how many unit cells?

0%
1 unit cell
0%
4 unit cells
0%
3 unit cells
0%
2 unit cells

The co-ordination number of hexagonal close packing:

0%
4
0%
6
0%
8
0%
12

Which of the following defects decrease the density?

0%
Interstitial defect
0%
Vacancy defect
0%
Frenkel defect
0%
Schottky defect

The number of spheres contained (i) in one body centred cubic unit cell and (ii) in one face centred cubic unit cell, is:

0%
In (i) $2$ and in (ii) $4$
0%
In (i) $3$ and in (ii) $2$
0%
In (i) $4$ and in (ii) $2$
0%
In (i) $2$ and in (ii) $3$

Explanation

The number of spheres in one body centred cubic and in one face centred cubic unit cell is

$2$ and

$4$ respectively.

A IS CORRECT OPTION

The three dimensional graph of lattice points which sets the pattern for the whole lattice is called:

0%
Space lattice
0%
simple lattice
0%
Unit cell
0%
Crystal lattice

Which of the following is not a characteristic of a crystalline solid?

0%
Definite and characteristic heat of fusion
0%
Isotropic nature
0%
A regular periodically repeated pattern of arrangement of constituent particles in the entire crystal
0%
A true solid

Explanation

$Anisotropy:$ Crystalline solids are anisotropic in nature, that is some of their physical properties like electrical resistance or refractive index show different values when measured along different directions in the same crystal. This arises from different arrangement of particles in different directions arrangement of particles along different directions.

$Isotropy:$ It is a characteristic of amorphous solid. Physical properties like electrical resistance or refractive index show same values when measured along different directions.
Option B is correct.

Which of the following is an example of metallic crystal solid?

0%
$C$
0%
$Si$
0%
$W$
0%
$AgCl$

When radius of central atom is double with respect to corner atoms, then find out % packing efficiency.

0%
$79$ %
0%
$90$ %
0%
$60$ %
0%
$65$ %

Explanation

$\sqrt { 3 } a=2r+2(2r)=6r$

$a=\cfrac { 6r }{ \sqrt { 3 } } =2\sqrt { 3 } r$

$P.F=\cfrac { \cfrac { 4 }{ 3 } \pi { r }^{ 3 }+\cfrac { 4 }{ 3 } \pi { (2r) }^{ 3 } }{ { a }^{ 3 } } \quad =\cfrac { \cfrac { 4 }{ 3 } \pi ({ r }^{ 3 }+{ 8r }^{ 3 }) }{ { (2\sqrt { 3 } r) }^{ 3 } } =\cfrac { 4\pi { \times 9r }^{ 3 } }{ 3\times 8\times 3\sqrt { 3 } { r }^{ 3 } } =\cfrac { \pi }{ 2\sqrt { 3 } } =0.906$

% of packing efficiency

$=0.906\times 100=90.6$ %

In a crystal, the atoms are located at the position of

0%
zero potential energy
0%
infinite potential energy
0%
minimum potential energy
0%
maximum potential energy

A match box exhibits _____ geometry.

0%
cubic
0%
orthorhombic
0%
triclinic
0%
monoclinic

Most crystals that show good cleavage because their atoms, ions or molecules are

0%
weakly bonded together
0%
strongly bonded together
0%
spherically symmetrical
0%
arranged in planes

In a crystal

$AB$ , which of the following crystal systems will have parameters,

$a\neq b\neq c$ and

$\alpha = \beta = \gamma = 90^{\circ}$ ?

0%
Cubic
0%
Orthorhombic
0%
Monoclinc
0%
Triclinic

The number of Bravais lattices in a cubic crystal is

0%
$3$
0%
$1$
0%
$4$
0%
$14$

The packing efficiency of the two dimensional square unit cell shown below is (all the circles are of the same radius).

0%
$39.27\%$
0%
$68.02\%$
0%
$74.05\%$
0%
$78.54\%$

Explanation

Number of atoms in

$2-D$ square unit cell

$=$ Number of corner atoms

$\times$ contribution to one unit cell

$= 4\times \dfrac {1}{4} = 1$

As the central atom is not shared by other cells.
Total number of atoms per square unit cell

$= 1 + 1 = 2$

$\therefore$ Packing fraction

$= \dfrac {\text {Area of atoms of one sq. unit cell}}{\text {Area of one sq. unit cell}}$

$= \dfrac {2\pi r^{2}}{l^{2}}$

where

$4r = \sqrt {2}l (From\ figure)$ .

So,

$r^2=\cfrac{l^2}{8} \Rightarrow \cfrac{r^2}{l^2}=\cfrac{1}{8}$

$\therefore$ Packing fraction= 0..785

$\%$ Packing

$= 78.5\%$

Option

$D$ is correct.

1557978_1738292_ans_5f56c268389740f7ad5668f29a890f5a.jpg

Which is the most unstable Bravais Lattice?

0%
Monoclinic
0%
Triclinic
0%
Romohedral
0%
Tetrahedral

The decreasing order of the size of the void is

0%
$Cubic > octahedral > tetrahedral > trigonal$
0%
$Trigonal > tetrahedral > octahedral > cubic$
0%
$Trigonal > octahedral > tetrahedral > cubic$
0%
$Cubic > tetrahedral > octahedral > trigonal$

Explanation

The decreasing order of the size of the void is:

$Cubic > octahedral > tetrahedral > trigonal$

The volume of the hexagonal prism is ( radius of every sphere is

$r$ )

0%
$24\sqrt 2 r^3$
0%
$16\sqrt 2 r^3$
0%
$12\sqrt 2 r^3$
0%
$\dfrac{64}{3\sqrt 3}r^3$

Explanation

Height of a unit cell:

$\mathrm{\sqrt{\cfrac{2}{3}}\times 4r}$

Base area of Hexagonal Prism :

$\mathrm{6 \times \sqrt{\cfrac{3}{4}} \times 2r^2}$

Volume of Hexagonal Prism =

$Base \ area \times Height \ of \ the \ Unit \ cell$ =

$\mathrm{6 \times \sqrt{\cfrac{3}{4}} \times 2r^2 \times \sqrt{\cfrac{2}{3}}\times 4r}$ =

$24 \sqrt2 \times r^3$ .

Hence, Option "A" is the correct answer.

How many atoms ( spheres ) are contained within the hexagonal prism shown below in h.c.p. space lattice?

0%
$2$
0%
$6$
0%
$12$
0%
$17$

Explanation

No. of atoms in a h.c.p cell =

$12 \times \cfrac{1}{6} + 2\times \cfrac{1}{2} + 3 \times 1$

$\implies$ No. of atoms in a h.c.p cell =

$6$

Hence, Option "B" is the correct answer.

In hexagonal close packing of sphere in three dimensions:

0%
In one unit cell there are 12 octahedral void and all are completely inside the unit cell.
0%
In one unit cell there are six octahedral voids and all are completely inside the unit cell.
0%
In one unit cell there are six octahedral void and of which three are completely inside the unit cell and other three are partially inside the unit cell.
0%
In one unit cell there are 12 tetrahedral voids, all are completely inside the unit cell.

Explanation

$HCP = AB\ AB\ AB$ ......................pattern repeat

For calculating voids between two layers

$A$ and

$B$ .

Total tetrahedral voids

$= 12$ (represented by dots)out of which

$8$ are completely inside but rest are shared by other unit cells.

Total octahedral voids

$=6$ (represented by cross). All are completely inside.

1591039_1746327_ans_a1cdd73dd38c4d6dbf18c89e129854f5.png

Select the correct statement (S) related to hexagonal close packing of identical spheres in three dimensions:

0%
In one unit cell there are 12 octahedral voids and all are completely inside the unit cell.
0%
In one unit cell there are six octahedral voids and all are completely inside the unit cell.
0%
In one unit cell there are six octahedral void and out of which three are completely inside the unit cell and other three are from contribution of octahedral void which are partially inside the unit cell
0%
Co-ordination number of every sphere is 12 in hcp lattice.

Explanation

HCP

$= AB\ AB\ AB$ ........................... pattern report

For calculation voids between two layers

$A$ and

$B$ .

Octahedral voids

$= 3 =$ represented by (*).

So total octahedral voids

$= 6=$ All are completely inside.

1590569_1746496_ans_5e07771fd1434e6cb283e2dda1c621ea.png

In this crystal of

$Fe_{0.93}O$ , the percentage of

$Fe(III)$ will be:

0%
$15\%$
0%
$85\%$
0%
$30\%$
0%
$78\%$

Explanation

$3x + (0.93 - x) \times 2 =2$

$x= 0.14$

$\%$ of

$Fe$ as

$Fe (III) = \dfrac{0.14}{0.93} \times 100 =15\%$

The cell content

$(Z)$ of the unit cell of a h.c.p. space lattice is

0%
$2$
0%
$6$
0%
$12$
0%
$17$

Explanation

The cell content

$(Z)$ of the unit cell of a h.c.p. space lattice is

$2$ .

Hence, Option "A" is the correct answer.

In melting lattice, structure of solid

0%
Remains unchanged
0%
Changes
0%
Become compact
0%
None of the above

Explanation

in melting lattice , struture of solid

$changes$ Because of the repeating geometric structure of the crystal, all the bonds between the particles have equal strength. A crystalline solid will have a distinct melting point, because applying heat will break all the bonds at the same time.

Bravais lattices are of:

0%
$8$ types
0%
$12$ types
0%
$14$ types
0%
$9$ types

Explanation

$14$ kinds of Bravais lattices (space lattices) are possible in a crystal.

Hence C is correct option

What is the packing fraction of

$_{26}^{56} Fe$ ?

(Isotopic mass = 55.92066)

0%
-14.167
0%
173.90
0%
-14.187
0%
-73.90

Explanation

Packing fraction =

$\dfrac{\text{Isotopic mass - Mass number}}{\text{Mass number}} \times 10^4$

$\dfrac{ 55.92066-56}{56}\times 10^4$

$-14.167$

Hence option (A) is correct.

Atom A possesses higher values of packing fraction than atom B. The relative stabilities of A and B are:

0%
A is more stable than B
0%
B is more stable than A
0%
A and B both are equally stable
0%
Stability does not depend on packing fraction

Explanation

The more negative the packing fraction of an element, the more stable should be the nucleus.

On the other hand, a positive packing fraction indicates that the nucleus should be less stable.

i.e. packing fraction is inversely proportional to the stability. So, the atom which has a lower value of packing fraction is stable.

Hence, option

$B$ is correct.

Points defects are present in

0%
Ionic solids
0%
Molecular solids
0%
Amorphous solids
0%
Liquids

Which of the following is an amorphous solid

0%
Glass
0%
Diamond
0%
Salt
0%
Sugar

Explanation

Such solids include glass, plastic, and gel. Quartz glass

$(SiO_2)$ is an amorphous solid due to its short range order of constituent particles. Note Quartz is a crystalline solid while quartz glass is an amorphous solid.

Which of the following features are not shown by quartz glass?

0%
This is a crystalline solid.
0%
Refractive index is same in all the directions.
0%
This has definite heat of fusion.
0%
This is also called supercooled liquid.

Amorphous solid can also be called as

0%
pseudo solids
0%
true solids
0%
super cooled liquids
0%
super cooled solids

Amorphous material are supercooled solids.

0%
True
0%
False

Explanation

$\text{ Given statement is }false.$

$\text{The amorphous solids are called as supercooled }liquid.$
Amorphous solids do not have a specific arrangement pattern. All amorphous solids have a tendency to flow through very slowly. That is why glass windows and doors become slightly thicker at the bottom than at the top with time.
Amorphous solids do not exhibit long order arrangement.

$\text{Option B is correct.}$

A crystal lattice is a periodic structure in

0%
$2$ dimension
0%
$3$ dimension
0%
vacuum space
0%
none

Explanation

$\text{A crystal lattice is a regular arrangement of the constituent atoms or ions or molecules in }three-dimensional$

$\text{space. A crystal lattice also called a space lattice or simply, a lattice. There are only 14 possible three-}$

$\text{dimensional lattices. These are called Bravais’ lattices.}$

Option B is correct.

1907369_1833151_ans_a7387b2162294f4fbf86b2180c6baac6.jpg

Stacking of square close packed layers give rise to:

0%
bcc structure
0%
fcc structure
0%
Simple cubic structure
0%
hcp structure

The neon atoms has a radius of

$160\,pm.$ What is the edge of the unit cell of a face centered structured of neon ?

0%
$490 \,pm$
0%
$320 \,pm$
0%
$453 \,pm$
0%
$481 \,pm$

Explanation

For body centered cubic crystals, the relation between side of unit cell (a) and radius of atom (r) is :

$a\sqrt2$ =

$4r$

Given, r = 160 pm

Hence, a =

$\cfrac{4r}{\sqrt2}$ =

$\cfrac{4\space \times \space 160}{\sqrt2}$ = 452.6 pm ≈ 453 pm.

Thus, option C is correct.

A crystalline material may be crystalline in more than one geometrical form.

0%
True
0%
False

Explanation

$\text{The given statement is }True$

$\text{Crystalline materials are the materials featuring highly ordered arrangements of their particles (atoms, ions, and}$

$\text{molecules) in microscopic structures.}$

$\text{A crystalline material may be crystalline in more than one geometrical form. There are several geometric forms in}$

$\text{which they may be crystalline are }triclinic, monoclinic, orthorhombic, tetragonal, trigonal, hexagonal, \text{ and }$

$\text{cubic. A family of crystals is determined by groupings of lattices and lines.}$

$\text{Option A is correct.}$

Which of the following has the smallest packing efficiency for atoms of a single type ?

0%
Body centered cubic
0%
Face centered cubic
0%
Simple cubic
0%
None of these

The numbers of tetrahedral and octahedral holes in a hexagonal primitive unit cell are :

0%
$8, 4$
0%
$6, 12$
0%
$2, 1$
0%
$12, 6$

In the close packing of atoms, there are :

0%
one tetrahedral void and two octahedral voids per atom
0%
two tetrahedral voids and one octahedral void per atom
0%
two of each tetrahedral and octahedral voids per atom
0%
one of each tetrahedral and octahedral void per atom

Graphite has h.c.p. arrangements of carbon atoms and the parallel planes are

$3.35 \,\mathring {A}$ apart. Determine density of graphite:

0%
$2.46 \,g/cc$
0%
$0.41 \,g/cc$
0%
$1 \,g/cc$
0%
$1.41 \,g/cc$

Explanation

In hcp arrangement total height

$h = 4 \times \sqrt{ \dfrac{2}{3}}r$
as per given

$\dfrac{h}{2} = 2 \sqrt{\dfrac{2}{3}}r = 3.35 \,\mathring {A} = 3.35 \times 10^{-8} \,cm.$
Volume of unit cell

$= 24 \sqrt{2}r^{3}$

$= 24 \sqrt{2} \left ( \sqrt{\dfrac{3}{2}} \times \dfrac{1}{2} \times 3.35 \times 10^{-8} \right )^{3}$

$= 2.93 \times 10^{-22} \,cm^{3}$
Effective no. of atoms in hexagonal unit cell

$= 6$

$\therefore density = \dfrac{6 \times 12}{6.023 \times 10^{23} \times 2.93 \times 10^{-22}}$

$= 0.41 \,g/cc$

Crystal System	Intercepts Parameter	Angle Parameter
Cubic	a = b = c	⍺ = β = γ = 90⁰
Orthorhombic	a ≠ b ≠ c	⍺ = β = γ = 90⁰
Monoclinic	a ≠ b ≠ c	⍺ = γ = 90⁰, β ≠ 90⁰
Triclinic	a ≠ b ≠ c	⍺ ≠ β ≠ γ ≠ 90⁰

CBSE Questions for Class 12 Engineering Chemistry The Solid State Quiz 11 - MCQExams.com

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Practice Class 12 Engineering Chemistry Quiz Questions and Answers

CBSE Questions for Class 12 Engineering Chemistry The Solid State Quiz 11 - MCQExams.com

0:0:1

Practice Class 12 Engineering Chemistry Quiz Questions and Answers

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