CBSE Questions for Class 12 Engineering Chemistry The Solid State Quiz 6 - MCQExams.com

The interstital hole is called tetrahedral because ?
  • it is formed by four spheres
  • partly same and partly different
  • it is formed by four spheres, the centres of which form a regular tetrahedron
  • none of the above
The lattices of Na and Al are bcc and fcc respectively. Presuming them to be closed packed, their packing fractions are, respectively :
  • $$0.68$$ and $$0.34$$
  • $$0.68$$ and $$0.74$$
  • $$0.34$$ and $$0.34$$
  • $$0.52$$ and $$0.52$$
The packing factor for a simple cubic lattice is :
  • $$\displaystyle \frac{\sqrt2 \pi}{6}$$
  • $$\displaystyle \frac{\pi}{6}$$
  • $$\displaystyle \frac{\sqrt3 \pi}{8}$$
  • $$\pi$$
In FCC unit cell, the percentage of unit cell not occupied by atoms is :
  • $$33\%$$
  • $$29\%$$
  • $$26\%$$
  • $$74\%$$
If A is the molecular mass of an element, a is the edge length and $$N$$ is the Avogadro's number, then the density for face-centered cubic lattice is :
  • $$\displaystyle\frac{4A}{Na^3}$$
  • $$\displaystyle\frac{2A}{Na^3}$$
  • $$\displaystyle\frac{A}{Na^3}$$
  • $$1$$
Which one of the following schemes of ordering closed packed sheets of equal sized spheres do not generate close packed lattice?
  • ABCABC
  • ABACABAC
  • ABBAABBA
  • ABCBCACBC
The volume of a crystal in BCC structure having N atoms is :
[a = edge length]
  • $$N_Aa^3$$
  • $$0.5N_Aa^3$$
  • $$0.33N_Aa^3$$
  • $$0.25N_Aa^3$$
If $$a$$ is the edge length, first three nearest neighbour distances for primitive cubic lattice are, respectively:
  • $$a,$$ $${\sqrt 2a},$$ $${\sqrt 3a}$$
  • $${\sqrt3a},$$ $${\sqrt2a},$$ $$a$$
  • $$a,$$ $${\sqrt2a},$$ $$2a$$
  • $$a,$$ $${\sqrt 3a},$$ $$2a$$
An atomic solid crystallizes in a body centre cubic lattice and the inner surface of the atoms at the adjacent corner are separated by $$60.3$$ pm. If the atomic weight of A is $$48$$, then the density of the solid is nearly:
  • $$2.7$$ g/cc
  • $$5.07$$ g/cc
  • $$3.5$$ g/cc
  • $$1.75$$ g/cc
The density of a pure substance A whose atoms are in cubic closed packed arrangement is $$1$$ g/cc. If all the tetrahedral voids are occupied by B atoms, what is the density (in g cm$$^{-3}$$) of resulting solid?[Atomic mass of $$A=30$$ g/mol and atomic mass of $$B=50$$ g/mol]
  • $$3.33$$
  • $$4.33$$
  • $$2.33$$
  • $$5.33$$
The density of solid argon (atomic mass $$=40$$ amu) is $$1.68$$ g/ml at $$40$$ K. If the argon atom is assumed to be a sphere of radius $${1.50 \times 10^{-8}}$$ cm, then the percentage of solid Ar which is space will be: 
[use $$N_A=6\times 10^{23}$$]
  • $$35.64$$
  • $$64.36$$
  • $$73$$
  • None of the above
The packing efficiency of a simple cubic crystal with an interstitial atom exactly fitting at the body center is:
  • $$0.48$$
  • $$0.52$$
  • $$0.73$$
  • $$0.91$$
Sodium (atomic mass $$=23$$ amu) crystallizes in a bcc arrangement with the interfacial separation between the atoms at the edge $$53.6$$ pm. The density (in g cm$$^{-3}$$) of sodium crystal is:
  • $$2.07$$
  • $$2.46$$
  • $$1.19$$
  • none of the above
Graphite has hcp arrangement of carbon atoms and the parallel planes are $$3.35$$ $$\mathring A$$ apart. The density (in g cm$$^{-3}$$) of graphite is :
  • $$2.46$$
  • $$2.12$$
  • $$1.20$$
  • $$1.41$$
Which of the following is a crystalline solid ?
  • Graphite
  • Calcite
  • Gallium
  • Oxygen
Select the correct statement(s).
  • A cubic system possesses a total of $$23$$ elements of symmetry
  • A cubic system contains a center of symmetry, planes of symmetry as well as axes of symmetry
  • For triclinic system, $${a\neq b\neq c}$$ and $$ {\alpha \neq \beta \neq \gamma \neq 90^{\circ}}$$
  • The total number of Bravais space lattices belonging to all the seven crystals is $$14$$
Packing fraction of an identical solid sphere is $$74\%$$ in:
  • simple cubic structure
  • fcc structure
  • hcp structure
  • bcc structure
Select the correct statement(s) :
  • The co-ordination number of each type of ion in a CsCl crystal is twelve.
  • A metal that crystallizes in a bcc structure has a co-ordination number of twelve.
  • A unit cell of an ionic crystal shares some of its ions with other unit cells.
  • The length of the unit cell in NaCl is $$552$$ pm (given that $${r_{Na+}= 85}$$ pm and $${r_{Cl-}= 181}$$ pm).
Which are amorphous solids?
  • Sodium chloride
  • Calcium flouride
  • Glass
  • Plastics
The density for an FCC lattice is: 

[A = atomic wt, N = Avogadro's number, a = lattice parameter]
  • $$\displaystyle \frac{4A}{Na^3}$$
  • $$\displaystyle \frac{2A}{Na^3}$$
  • $$\displaystyle \frac{A}{Na^3}$$
  • $$\displaystyle \frac{A}{Na^2}$$
Stacking of hexagonal close packed layer gives rise to:
  • bcc structure
  • hcp structure
  • fcc structure
  • sc structure
Which of the following contains only one Bravais lattice?
  • Hexagonal
  • Monoclinic
  • Rhombohedral
  • Triclinic
Correct order for lattice energy of the given crystals is :
  • $$KCl < NaCl < NaF$$
  • $$NaF > KCl > NaCl$$
  • $$KCl > NaCl > NaF$$
  • $$NaF < NaCl < KCl$$
The elements of symmetry in a crystal are:
  • plane of symmetry
  • axis of symmetry
  • centre of symmetry
  • none of these
Which of the following is not an amorphous substance?
  • Copper
  • Rubber
  • Glass
  • Polymers
Crystalline solids do not have :
  • a definite latent heat of fusion.
  • irregular atomic arrangement.
  • incompressibility.
  • free movement of atoms.
If $$A$$ is the atomic mass number of an element, $$N$$ is the Avogadro number and $$a$$ is the lattice parameter, then the density of the element, if it has bcc crystal structure, is_________.
  • $$\displaystyle \dfrac{A}{Na^3}$$
  • $$\displaystyle \dfrac{2A}{Na^3}$$
  • $$\displaystyle \dfrac{\sqrt 3 A}{Na^3}$$
  • $$\displaystyle \dfrac{2\sqrt 2A}{Na^3}$$
Stacking (a pile) of square close packed layer gives rise to:
  • BCC structure
  • FCC strncture
  • SC structure
  • none of the above
Statement: The unit cell of many metals is one of the three cubic unit cells.

State whether the given statement is true or false.
  • True
  • False
Statement: Face-centred cubic structure possesses the most close packing of atoms in it.

State whether the given statement is true or false
  • True
  • False
State whether the given statement is true or false:
 Diamond is the hardest compound.
  • True
  • False
Statement: Glass is supercooled liquid.

State whether the given statement is true or false.
  • True
  • False
Lattice energy of NaCl is $$-186$$ kcal/mol. If solution enthalpies of Na$$+$$ and Cl$$^-$$ are $$-97$$ kcal/mol and $$-85$$ kcal/mol respectively. The enthalpy NaCl solution in kcal will be:
  • $$-4$$
  • $$182$$
  • $$368$$
  • $$4$$
Statement: The imperfectness in crystal increases with increase in temperature.

State whether the given statement is true or false
  • True
  • False
Statement: At $$0$$ Kelvin, crystals have a perfect orderly arrangement.

State whether the given statement is true or false
  • True
  • False
If the radius of $$B ^-$$ ion is $$0.180$$ nm, the size (in nm) of the cation that can fit in the tetrahedral void is:
  • $$0.125$$
  • $$0.04$$
  • $$0.08$$
  • $$0.180$$
If a diamond has a face-centered cubic structure with two atoms per lattice point and a unit cell of the edge of $$3.569\:\mathring{A}$$. The density (in g cm$$^{-3}$$) of the diamond is :
  • $$3.569$$
  • $$2.569$$
  • $$1.899$$
  • $$7.946$$
MgO has NaCl type structure and its unit cell edge length is $$421$$ pm. Its density (in g cm$$^{-3}$$) will be:
  • $$3.54$$
  • $$1.46$$
  • $$2.14$$
  • None of the above
Select the correct order for covalent radii :
  • Octahedral radii > linear radii > tetrahedral radii
  • Octahedral radii > tetrahedral radii > linear radii
  • Linear radii > tetrahedral radii > octahedral radii
  • Tetrahedral radii > octahedral radii > linear radii
Metallic copper crystallises in bcc lattice. The length of the cubic unit cell is $$362$$ pm. The density (in g cm$$^{-3}$$) of crystalline copper is:
  • $$2.78$$
  • $$3.51$$
  • $$4.45$$
  • none of the above
Truncated octahedral (cube-octahedra) is called 'case' or 'sodalite cage'.
  • True
  • False
The ratio of packing density in fcc, bcc and cubic structure is respectively_________.
  • $$1:0.92 :0.70$$
  • $$0.70 :0.92 :1$$
  • $$1:0.70:0.92$$
  • $$0.92:0.70:1$$
Lithium borohydride $$(LiBH_4) $$ 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 of the compound is $$21.76$$ g/mol, the density (in g cm$$^{-3}$$) of the compound will be:
  • $$0.67$$
  • $$0.33$$
  • $$1.72$$
  • none of the above
If the effective radius of iron (Fe) atom is $$141.4$$ pm which has rock salt type structure, then its density (in g cm$$^{-3}$$) will be: 
[$$Fe = 56$$ amu]
  • $$5.81$$
  • $$2.63$$
  • $$1.08$$
  • None of the above
In which of the following systems, interfacial angles $$\alpha = \gamma = 90^o$$ but $$\beta \neq 90^o$$?
  • Monoclinic
  • Rhombohedral
  • Triclinic
  • Hexagonal
The total fraction of space occupied by voids in simple cubic structure is:
  • $$0.58$$
  • $$0.25$$
  • $$0.48$$
  • $$0.86$$
The compound CuCl has zinc blende structure and the edge length of its unit cell is $$500$$ pm, its density (in g cm$$^{-3}$$) is :
(Given that the atomic weight of $$Cu$$ is $$63.5$$ amu and of $$Cl $$ is $$35.5$$ amu.)
  • $$5.24$$
  • $$1.14$$
  • $$2.99$$
  • None of the above
The packing fraction for a body-centered cube is________.
  • $$0.42$$
  • $$0.53$$
  • $$0.68$$
  • $$0.82$$
Which of the following systems have lattice parameters as $$a\neq b \neq c$$?
  • Orthorhombic
  • Monoclinic
  • Triclinic
  • Hexagonal
The space in which atoms are not present in unit cell is :
  • $$48\%$$ in simple cubic
  • $$32\%$$ in body-centred cubic
  • $$26\%$$ in face-centred cubic
  • $$26\%$$ in hexagonal
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