SOLID-STATE-QUIZ-3

Solid State Quiz-3

Dear Readers,

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Q1. Which kind of defect is shown by the given crystal?

•  Schottky defect
•  Frenkel defect
•  Schottky and Frenkel defects
•  Substitution disorder

Solution
In the given crystal equal number of cations and anions are missing (two K+ and two Cl−) from their normal lattice sites and the crystal maintains electrical neutrality. Hence, this is Schottky defect.

Q2.The number of atoms (n) contained within a body centred cubic cell is:

•  1
•  2
•  3
•  4

Solution
The body centred cubic cell consists of 8 atoms at the corners and one atom at centre. 

 ∴n= (8 ×1/8)+1=2

Q3.  In a solid lattice, the cation has left a lattice site and is located at an interstitial position, the lattice

defect is

•   Frenkel defect
•  Schottky defect
•  F-centre defect
•  Valency defect

Solution
When an ion (generally cation due to its small size) is missing from its normal position and occupy an interstitial site between the lattice points, the lattice defect obtained is known as Frenkel defect.

Q4. Which of the following statements are true?

•  Piezo-electricity is due to net dipole moment
•  Ferro-electricity is due to alignment of dipoles in same direction
•  Pyro-electricity is due to heating polar crystals
•  All of the above

Solution
All these are characteristic facts.

Q5.A match box exhibits :

•  Cubic geometry
•  Monoclinic geometry
•  Orthorhombic geometry
•  Tetragonal geometry

Solution
 Orthorhombic geometry has a≠b≠c and α=β=γ=90°. The shape of match box obey this geometry.

Q6. The statement that “All crystals of the same substance possess the same elements of symmetry”

is known as :

•  Hauy’s law of rationality of indices
•  The law of constancy of interfacial angles
• The law of constancy of symmetry
•  None of the above

Solution
This is the law of constancy of symmetry.

Q7.Metallic crystalline solids :

•  Have low melting point and boiling point
•  Are bad conductors
•  Are good conductors of heat and electricity
•  Only conduct heat

Solution
It is a fact.

Q8.If NaCl is dopped withthe concentration of cation vacancies will be:

•  
•  
•  
•  

Solution
Dopping of to NaCl brings in replacement of twoby eachion, butoccupies one lattice point. This produces one cation vacancy.

No. of cation vacancies =

100 mole of NaCl will have cationic vacancy =

∴ 1 mole of NaCl will have cationic vacancy =

∴ No. of cationic vacancies =

Q9.8 : 8 co-ordination of CsCl is found to change into 6 : 6 co-ordination on :

•  Applying pressure
•  Increasing temperature
•  Both (a) and (b)
•  None of these

Solution
High temperature changes 8 : 8 co-ordination to 6 : 6 whereas high pressure changes 6:6 co-ordination to 8 : 8.

Q10. Which crystal is expected to be soft and have low melting point?

•  Covalent
•  Metallic
•  Molecular
• Ionic

Solution
Follow characteristics of molecular solids.