Solid state most important questions for board and jee exam-Part-1

Why do we study solid state chemistry?

To obtain the knowledge on design and development of materials with pre-required properties based on understanding the structure of solids in its influence on physical-chemical properties, understanding of phase relations, chemical synthesis, reaction kinetics as well as characterisation methods.

What is the fundamental concept in solid state chemistry?

solid is a material in the solid stateSolid state chemistry is the branch of chemistry that deals with the representation of the structure, properties and applications, for example in mineralogy and crystallography, metallurgy and in the Materials Sciences of these substances.

What is solid state and its types?

There are two main categories of solids: crystalline and amorphous. Crystalline solids are well ordered at the atomic level, and amorphous solids are disordered. There are four different types of crystalline solids: molecular solids, network solids, ionic solids, and metallic solids.

What are the properties of solid state?

Definite mass, volume, and shape. Short Intermolecular distance. Strong Intermolecular Forces. The constituent particles remain fixed at their positions and can only oscillate about their mean positions.

25 Most important questions on solid state for class 12th and JEE Exam

Question 1: Which point defect in its crystal units alters the density of a solid?
Answer: Schottky defect.

Question 2
Write a distinguishing feature between a metallic solid and an ionic solid.
Answer:
The electrical conductivity in metallic substances is due to free electrons while in ionic substances the conductivity is due to presence of ions.

Question 3
Why are crystalline solids anisotropic?
Answer:
Crystalline solids show different values of their some properties like electrical conductivity, refractive index, thermal expansion etc. in different directions.

Question 4
What is meant by ‘antiferromagnetism’?
Answer:
Antiferromagnetism : These substances possess zero net magnetic moment because of presence of equal number of electrons with opposite spins.

Question 5.
Write a distinguishing feature of a metallic solid compared to an ionic solid.
Answer:
Metallic solid conducts electricity in solid state but ionic solids do so only in molten state or in solution or metals conduct electricity through electrons and ionic substances through ions. Metallic solids are malleable and ductile while ionic solids are hard and brittle.

Question 6
What is the formula of a compound in which the element Y forms ccp lattice and atoms of X occupy 1/3rd of tetrahedral voids?
Answer:
Formula is X2Y3.

Question 7.
What is the formula of a compound in which the element Y forms ccp lattice and atoms of X occupy 2/3rd of tetrahedral voids?
Answer:
Y atoms are N (No. of tetrahedral voids are 2N), No. of tetrahedral voids occupied by X are
23 × 2N = 4N3
X : Y = 4N : 3N
Formula : X4Y3

Question 8
What is the no. of atoms per unit cell (z) in a body-centred cubic structure?
Answer:
Contribution by the atoms present at eight comers = 8 × 18 = 1
Contribution by the atoms present at centre = 1
Total number of atoms present in unit cell = 1 + 1 = 2

Question 9.
What type of stoichiometric defect is shown by AgCl?
Answer:
AgCl shows Frenkel defect.

Question 10.
Give an example each of a molecular solid and an ionic solid.
Answer:
Molecular solid → Iodine (I2)
Ionic solid → Sodium chloride (NaCl)

Question 11
Which point defect in crystals of a solid does not change the density of the solid?
Answer:
Frenkel defect.

Question 12
Which point defect in crystals of a solid decreases the density of the solid?
Answer:
Schottky defect.

IIT JEE Mains & Advance Toppers Handwritten Notes – Complete Study Material – 14 books -Latest Edition

Question 13.
What type of interactions hold the molecules together in a polar molecular solid?
Answer:
Dipole-dipole forces of attractions hold the molecules together in a polar molecular solid.

Question 14.
What type of semiconductor is obtained when silicon is doped with arsenic?
Answer:
n-type semiconductor.

Question 15.
Write a distinguishing feature of metallic solids.
Answer:
Metallic solids possess high electrical and thermal conductivity due to presence of free electrons.

Question 16.
‘Crystalline solids are anisotropic in nature.’ What does this statement mean?
Answer:
It means that crystalline solids show different values of their some properties like electrical conductivity, refractive index, thermal expansion etc. in different directions.

Question 17.
Which stoichiometric defect in crystals increases the density of a solid?
Answer:
Interstitial defect in crystals increases the density of a solid.

Question 18.
What is meant by ‘doping’ in a semiconductor?
Answer:
Addition of a suitable impurity to a semiconductor to increase its conductivity is called doping.

Question 19.
Write a point of distinction between a metallic solid and an ionic solid other than metallic lustre.
Answer:
Metallic solid conducts electricity in solid state but ionic solids do so only in molten state or in solution or metals conduct electricity through electrons and ionic substances through ions. Metallic solids are malleable and ductile while ionic solids are hard and brittle.

Question 20.
How may the conductivity of an intrinsic semiconductor be increased?
Answer:
The conductivity is increased by adding an appropriate amount of suitable impurity. This process is called as intrinsic doping.

Question 21.
Which stoichiometric defect increases the density of a solid?
Answer:
Interstitial defect increases the density of a solid.

Question 22.
What are n-type semiconductors?
Answer:
n-type semiconductor : They are obtained by doping silicon with an element of group15, like P, As etc.

Question 23.
What type of stoichmetric defect is shown by AgBr and Agl ?
Answer:
AgBr shows both Frenkel defect and Schottky defect whereas Agl shows Frenkel defect.

Question 24.
What type of defect can arise when a solid is heated ?
Answer:
Vacancy defects can arise when a solid is heated.

Question 25.
Why does LiCl acquire pink colour when heated in Li vapours?
Answer:
This is due to metal excess defect due to anionic vacancies in which the anionic sites are occupied by unpaired electrons (F-centres).

Best Refference books and notes for class 12th and JEE/NEET Exam

IIT JEE Mains & Advance Toppers Handwritten Notes – Complete Study Material – 14 books -Latest Edition

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