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

Silver crystallizes in a fcc lattice and has a density of $$10.6 \,g/cm^3$$. What is the length of an edge of the unit cell ?
  • $$0.407 \,nm$$
  • $$0.2035 \,nm$$
  • $$0.101 \,nm$$
  • $$4.07 \,nm$$
An element crystallizes in a structure having FCC unit cell of an edge length $$200$$ pm. If $$200$$ g of this element contains $$24\times 10$$ $$^{23}$$ atoms, the density (in g/cc) of the element is :
  • $$50.3$$
  • $$63.4$$ 
  • $$41.6$$
  • $$34.8$$
The number of hexagonal faces that are present in a truncated octahedron is:
  • $$8$$
  • $$9$$
  • $$10$$
  • $$11$$
The packing efficiency of the two-dimensional square unit cell shown in the given figure is :

32067_3f7e138abe744bcb8cfb500633943389.png
  • $$39.27\%$$
  • $$68.02\%$$
  • $$74.05\%$$
  • $$78.54\%$$
An element crystallizes in a structure having FCC unit cell of an edge length $$200$$ pm. Calculate the density (in g cm$$^{-3}$$) if $$200$$ grams of it contains $$24\times 10^{23}$$ atoms.
  • $$41.6$$
  • $$42.6$$
  • $$43.6$$
  • $$44.6$$
A solid made up of ions of A and B possesses an edge length of unit cell equal to $$0.564$$ nm has four formula units. Among the two ions, the smaller one occupies the interstitial void and the larger ions occupy the space lattice with ccp type of arrangement. One molecule of solid has mass as $$9.712\times10^{-23}$$ g. The density (in g cm$$^{-3}$$) of solid is:
  • $$2.16$$
  • $$0.54$$
  • $$1.08$$
  • $$1.562$$
The empty space in this HCP unit cell is :
  • $$74\%$$
  • $$47.6\%$$
  • $$32\%$$
  • $$26\%$$
Assertion: The close packing of atoms in cubic structure is in the order: scp > bcc > ccp.

Reason: $$\text{Packing density} = \dfrac{\text{Volume of unit cell}}{a^{3}} $$
  • Both Assertion and Reason are correct and Reason is correct explanation of Assertion.
  • Both Assertion and Reason are correct but Reason is not a correct explanation of Assertion.
  • Assertion is wrong but Reason is correct.
  • Assertion is correct but Reason is not correct.
Match the elements in list I with the shape of its crystal in list II.
List IList II
A) $$Be$$1) Body-centred cubic
B) $$Ca$$2) Simple cubic
C) $$Ba$$3) Face-centred cubic
D) $$Po$$4) Hexagonal close-packed
  • A - 4, B-3, C-1, D-2
  • A - 4, B-3, C-2, D-1
  • A-2, B-4, C-1, D-3
  • A-4, B-1, C-3, D-2
If the edge length of an NaH unit cell is $$488$$ pm, what is the length of an Na-H bond if its crystal has fcc structure?
  • $$488$$ pm
  • $$122$$ pm
  • $$244$$ pm
  • $$976$$ pm
Calculate the density (in g cm$$^{-3}$$) of diamond from the fact that it has face-centered cubic structure with two atoms per lattice point and unit cell edge length of $$3.569\, \mathring A$$.
  • $$7.5$$
  • $$1.7$$
  • $$3.5$$
  • None of the above
Which of the following statements are true?
  • The unit cell content of potassium which crystallizes in body centered cubic unit cell is two
  • For the planes, $$(100), (110),\ (111)$$ in a cubic unit cell, the ratio of $$d_{100},\ d_{110}$$ and $$d_{111}$$ is $$\sqrt{2} : 1 :\sqrt{\dfrac{2}{3}}$$
  • A cubic crystal has total $$23$$ elements of symmetry
  • In tetragonal crystal system, the number of Bravais lattices is only two
Lithium metal crystallizes in a body-centered cubic crystal. If the length of the side of the unit cell of lithium is 351 pm, the atomic radius of lithium will be:
  • 300.5 pm
  • 240.8 pm
  • 151.98 pm
  • 75.5 pm
Fraction of empty space in ABAB type arrangement in 3D is :
  • $$0.74$$
  • $$0.26$$
  • $$0.68$$
  • $$0.32$$
The face centred cubic cell of platinum has a length of $$0.392 nm$$. Calculate the density of platinum $$(g/cm^3): $$

(Atomic weight  : Pt=195)
  • 20.9
  • 20.4
  • 19.6
  • 21
The pyknometric density of sodium chloride crystal is $$2.165\times 10^{3}\ kg\ m^{-3}$$ while its X-ray density is $$2.178\times 10^{3} kg\ m^{-3}$$. The fraction of unoccupied sites in sodium chloride crystal is:
  • $$5.96\times 10^{-3}$$
  • $$5.96$$
  • $$5.96\times 10^{-2}$$
  • $$5.96\times 10^{-1}$$
Statement 1: Increasing temperature increases the density of point defects.
Statement 2: The process of formation of point defects in solids is endothermic and has $$\Delta S > 0$$.
  • Statement-1 is true, Statement-2 is true and Statement-2 is the correct explanation for Statement-1
  • Statement-1 is true, Statement-2 is true and Statement-2 is not the correct explanation for Statement-1
  • Statement-1 is true, Statement-2 is false
  • Statement-1 is false, Statement-2 is true
Which of the following can conduct electricity in a fused state?
  • $$MgCl_2$$
  • $$CaCl_2$$
  • $$BaCl_2$$
  • $$BeCl_2$$
If the edge length is $$3.60A^o$$, density of diamond crystal is:
  • 3.92 gm/cc
  • 2.40 gm/cc
  • 3.37 gm/cc
  • 2.58 gm/cc.
In a monoclinic unit cell, the relation of sides and angles are, respectively :
  • $$a=b\neq c$$ and $$\alpha =\beta =\gamma =90^o$$
  • $$a\neq b\neq c$$ and $$\alpha =\beta =\gamma =90^o$$
  • $$a\neq b\neq c$$ and $$\beta =\gamma =90^o\neq \alpha$$
  • $$a\neq b\neq c$$ and $$\alpha \neq \beta \neq \gamma \neq 90^o$$
An element crystallizes in a structure having FCC unit cell of an edge length equal to $$200$$ pm. Calculate the density (in g cm$$^{-3}$$) if $$200$$ g of this element contains $$24\times10^{23}$$ atoms.
  • $$41.67$$
  • $$83.34$$
  • $$119.43$$
  • None of the above
Gold crystallizes in a face centered cubic lattice. If the length of the edge of the unit cell is $$407$$ pm, calculate the density of gold as well as its atomic radius assuming it to be spherical. Atomic mass of gold $$=197$$ amu.
  • $$19.4\:g/cm^{3}$$, $$143.9$$ pm
  • $$38.8\:g/cm^{3}$$, $$ 143.9$$ pm
  • $$19.4\:g/cm^{3}$$, $$287.8$$ pm
  • None of the above
The distance between an octahedral and tetrahedral void in fcc lattice would be
  • $${\sqrt 3a}$$
  • $$\displaystyle\frac{\sqrt{3a}}{2}$$
  • $$\displaystyle\frac{\sqrt{3a}}{3}$$
  • $$\displaystyle\frac{\sqrt{3}a}{4}$$
The density of crystalline $$CsCl$$ is $$3.988\ g/cc$$. The volume effectively occupied by a single $$CsCl$$ ion pair in the crystal is
  • $$7.014\times 10^{-23} cc$$
  • $$2.81\times 10^{-22} cc$$
  • $$6.022\times 10^{-23} cc$$
  • $$3.004\times 10^{-23} cc$$
An element X (atomic weight $$= 24$$ amu) forms a face-centred cubic lattice. If the edge length of the lattice is $${4\times10^{- 8}}$$ cm and the observed density is $$2.40 \times 10^{3}$$ kg m$$^{-3}$$, then the percentage occupancy of lattice points by element X is: (use $$ {N_{A}= 6\times 10^{23}}$$)
  • $$96$$
  • $$98$$
  • $$99$$
  • none of the above
Iron occurs as bcc as well as fcc unit cell. If the effective radius of an atom of iron is $$124$$ pm, the density (in g cm$$^{-3}$$) of iron in both these structures are, respectively :
  • $$7.887,\ 8.59$$
  • $$8.59,\ 7.887$$
  • $$14.287,\ 16.248$$
  • $$16.248,\ 14.287$$
The arrangement of $$X^{-}$$ ions around $$A^{-}$$ ion in solid $$AX$$ is given in the figure (not drawn to scale). If the radius of $$X^{-}$$ is $$250\ pm$$, the radius of $$A^{+}$$ is
153656_49aa3f6fe4574bf783e78c4bbed8df4f.jpg
  • $$104pm$$
  • $$125pm$$
  • $$183pm$$
  • $$57pm$$
Select the correct statement(s) about three-dimensional hcp system.
  • The number of atoms in hcp unit cell is $$6$$.
  • The volume of hcp unit cell is $$24 \sqrt 2 r^3$$.
  • The empty space in hcp unit cell is $$26\%$$.
  • The base area of hcp unit cell is $$6\sqrt 3 r^2$$.
Which of the following statements are correct?
  • Dislocation of ion from lattice site to interstitial site is called Frenkel defect.
  • Missing of +ve and -ve ions from their respective position producing a pair of holes is called Schottky defect.
  • The presence of ions in the vacant interstital sites along with lattice point is called interstital defect.
  • Non-stoichiometric $$NaCl$$ is yellow solid.
The density of KBr is $$2.75$$ g cm$$^{-3}$$. The length of the unit cell is $$654$$ pm. Atomic mass of K $$= 39$$ amu, Br $$= 80$$ amu.  What is true about the predicted nature of the solid?
  • The unit cell is fcc.
  • The number of atoms per unit cell is $$4$$.
  • There are four constituents per unit cell.
  • There are $$8$$ ions at the corners and $$6$$ at the centres of the faces.
For orthorhombic system axial ratios are $$a\neq b\neq c$$ and the axial angles are
  •  $$\alpha = \beta = \gamma \neq 90^o$$
  •  $$\alpha = \beta = \gamma = 90^o$$
  • $$\alpha = \gamma= 90^o , \beta \neq 90^o$$
  • $$\alpha \neq \beta \neq \gamma = 90^o$$
A metallic crystal crystallizes into a lattice containing a sequence of layers $$ABABAB$$.... Any packing of spheres leaves out voids in the lattice. What percentage by volume of this lattice is empty space ?
  • $$74$$%
  • $$26$$%
  • $$50$$%
  • $$None\ of\ these$$
The $$\gamma$$-form of iron has fcc structure (edge length $$=386$$ pm) and $$\beta$$-form has bcc structure (edge length $$=290$$ pm). The ratio of density in $$\gamma$$-form to that in $$\beta$$-form is :
  • $$0.85$$
  • $$1.02$$
  • $$1.57$$
  • $$0.6344$$
Identical spheres are undergoing two-dimensional packing in square close packing and hexagonal close packing. Which of the following statements are correct regarding the spheres?
  • The ratio of coordination number for a sphere in first case to that in second case is $$2 : 3$$.
  • Packing in second case is more effective.
  • Packing in first case is more effective.
  • The stacking of layer on first type packing produces simple cubic structure.
If the lattice parameter of Si is $$5.43$$ $$\mathring {A} $$ and the mass of Si atom is $$28.08 \times 1.66 \times 10^{-27}$$ kg, the density of silicon in kg m$$^{-3}$$ is:
[Given: Silicon has a diamond cubic structure.]
  • $$2330$$
  • $$1115$$
  • $$3445$$
  • $$1673$$
Which of the following characteristic features match(es) with the crystal systems: cubic and tetragonal
  • Both have the cell parameters; $$a=b=c$$ and $$\alpha =\beta =\gamma$$
  • Both belong to different crystal systems
  • Both have only two crystallographic angles of $$90^o$$
  • Both belong to same crystal system
If the radius of the spheres in the close packing is R and the radius of octahedral voids is r, then r $$= 0.414$$ R.
  • True
  • False
A metal crystallizes in bcc lattice. The percent fraction of edge length not covered by atom is :
  • $$10.4\%$$
  • $$13.4\%$$
  • $$12.4\%$$
  • $$11.4\%$$
A metal crystallizes into two cubic phases, face-centered cubic and body-centered cubic which have unit cell lengths as $$3.5\ \mathring A$$ and $$3.0\ \mathring {A} $$, respectively. Calculate the ratio of densities of fcc and bcc.
  • $$1.26$$
  • $$3.25$$
  • $$\sqrt2$$
  • None of the above

The packing efficiency of a two-dimensional square unit cell shown is __________.
252432_b674502af3394b92aa5d30c3e021bdf2.png
  • 39.27%
  • 68.02%
  • 74.05%
  • 78.57%
An element crystallizes in a structure having FCC unit cell of an edge length $$200$$ pm. Calculate the density (in g cm$$^{-3}$$) if $$200$$ g of this element contain $$5\, \times\, 10^{24}$$ atoms.
  • $$5$$
  • $$30$$
  • $$10$$
  • $$20$$
The pattern of successive layers of ccp arrangement can be designated as:
  • AB AB AB
  • AB ABC AB ABC
  • ABC ABC ABC
  • AB BA AB BA
Statement: Packing fraction of FCC and HCP units cells are the same.

State whether the given statement is true or false.
  • True
  • False
An element has a FCC structure with edge length 200 pm. Calculate density if 200 g of this element contains $$24 \times 10^{23}$$ atoms.
  • $$4.16\ g cm^{-3}$$
  • $$41.6\ g cm^{-3}$$
  • $$4.16\ kg cm^{-3}$$
  • $$41.6\ kg m^{-3}$$
Which of the following does not posses any plane of symmetry?
  • Cubic
  • Monoclinic
  • Triclinic
  • Rhombohedral
Calculate the void fraction per unit volume of unit cell for such crystal.
  • 0.236
  • 0.67
  • 0.45
  • 0.82
The packing efficiency of the two dimensional square unit cell shown below is  :
319261_d4e05ff70bf14cae86d5eb2bf74ef63b.png
  • $$39.27\%$$
  • $$68.02\%$$
  • $$74.05\%$$
  • $$78.57\%$$
The crystal with $$a=  b \neq c, \alpha = \beta =\gamma =90^o$$ is:
  • cubic
  • orthorhombic
  • tetragonal
  • hexagonal
Lithium borohydride crystallizes in an orthorhombic system with $$4$$ molecules per unit cell. The unit cell dimensions are $$a=6.8\:\mathring{A}$$, $$b=4.4\:\mathring{A}$$ and $$c=7.2\:\mathring{A}$$. If the molar mass is 
$$21.76$$ g mol$$^{-1}$$, calculate the density (in g cm$$^{-3}$$) of crystal.
  • $$1.34$$
  • $$0.87$$
  • $$0.94$$
  • $$0.67$$
CsBr crystallizes in a body-centred cubic lattice of unit cell edge length $$436.6$$ pm. Atomic masses of Cs and Br are $$133$$ amu and $$80$$ amu respectively. The density (in g cm$$^{-3}$$) of CsBr is :
  • $$8.50$$
  • $$4.25$$
  • $$42.5$$
  • $$0.425$$
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