Topic wise important and hots questions from Solid state

                                                  Class –XII Solid State                                                              

S.No.	Chapter Name	Topic-Concept Name	VSA/SA/long answer question
1	Solid State	General Characteristics of Solid State	VSA-36 SA TYPE-I (2MARKS)-18 SA TYPE-II (3MARKS)-8   Note - This time (Session2020-21), CBSE has removed Electrical Properties, Magnetic Properties from board exam. So, you can leave these topic to get good score for board exams
		Amorphous and Crystalline Solids
		Classification of Crystalline Solids
		Crystal Lattices and Unit Cells
		Number of Atoms in A Unit Cell
		Close Packed Structures
		Packing Efficiency
		Calculations Involving Unit Cell Dimensions
		Imperfections in Solids
		Electrical Properties
		Magnetic Properties

VERY SHORT ANSWER TYPE QUESTIONS (1 Mark) 

S.No.	Topic-Concept Name	VSA (1 Marks)
1	Close Packed Structures	What is the coordination number of each type of ions in a rock-salt type crystal structure?
2	Number of Atoms in A Unit Cell	What is the total number of atoms per unit cell in a face-centred cubic (fcc) structure?
3	Magnetic Properties	What type of substances exhibit anti-ferromagnetism?
4	Electrical Properties	Define the ‘forbidden zone’ of an insulator.
5	Imperfections in Solids	Which crystal defect lowers the density of a solid?
6	Electrical Properties	Name an element with which silicon may be doped to give a p-type semiconductor.
7	Imperfections in Solids	Which point defect in crystals does not alter the density of the relevant solid?
8	Imperfections in Solids	Which point defect in its crystal units increases the density of a solid?
9	Electrical Properties	How do metallic and ionic substances differ in conducting electricity?
10	Crystal Lattices and Unit Cells	What is the number of atoms in a body-centred cubic unit cell of a crystal?
11	Classification of Crystalline Solids	Write a feature which will distinguish a metallic solid from an ionic solid.
12	Classification of Crystalline Solids	What type of interactions hold the molecules together in a polar molecular solid?
13	General Characteristics of Solid State	Account on the following- a) Liquids and gases categorized as fluid b) Solids incompressible
14	Electrical Properties	What type of semiconductor is obtained when silicon is doped with arsenic?
15	Classification of Crystalline Solids	Write a distinguishing feature of metallic solids?
16	Crystal Lattices and Unit Cells	What is the number of atoms in a unit cell of a simple cubic crystal?
17	Amorphous and Crystalline Solids	‘Crystalline solids are anisotropic in nature.’ What does this statement mean?
18	Crystal Lattices and Unit Cells	Define terms unit cell in relation to crystalline solids:
19	Electrical Properties	What is meant by an ‘intrinsic semiconductor’?
20	Electrical Properties	What is meant by ‘doping’ in a semiconductor?
21	Classification of Crystalline Solids	Write a point of distinction between a metallic solid and an ionic solid other than metallic lustre.
22	Electrical Properties	How may the conductivity of an intrinsic semiconductor be increased?
23	Magnetic Properties	Define paramagnetism with an example.
24	Imperfections in Solids	What type of point defect is produced when AgCl is doped with CdCl2?
25	Imperfections in Solids	What type of stoichiometric defect is shown by AgCl?
26	Magnetic Properties	What type of substances would make better permanent magnets, ferromagnetic or ferrimagnetic?
27	Classification of Crystalline Solids	Which group of solids is electrical conductors, as well as malleable and ductile?
28	Classification of Crystalline Solids	Why glass is considered a supercooled liquid?
29	Close Packed Structures	What is the two-dimensional coordination number of a molecule in a square close-packed layer?
30	Imperfections in Solids	Define F-centers.
31	Magnetic Properties	What happens when a ferromagnetic substance is subjected to high temperature?
32	Amorphous and Crystalline Solids	Define term amorphous amorphous.
33	Close Packed Structures	What are the  co-ordination  numbers  of  octahedral  voids  and  tetrahedral voids ?
34	Imperfections in Solids	CaCl2 will introduce Schottky defect if added to AgCl crystal. Explain.
35	Amorphous and Crystalline Solids	What is the difference between glass and quartz do both contain silicate unit?
36	Amorphous and Crystalline Solids	Which property of glass enables it to be molded and blown in to various shapes

 

 SHORT ANSWER-I TYPE QUESTIONS (2 Marks)

 

S.No.	Topic-Concept Name	SA (2 Marks)
37	Calculations Involving Unit Cell Dimensions	Silver crystallizes with face-centered cubic unit cells. Each side of the unit cell has a length of 409 pm. What is the radius of an atom of silver? (Assume that each face atom is touching the four corner atoms.)
38	Calculations Involving Unit Cell Dimensions	Explain how you can determine the atomic mass of an unknown metal if you know its mass density and the dimensions of unit cell of its crystal.
39	Packing Efficiency	Calculate the packing efficiency of a metal crystal for a simple cubic lattice.
40	Imperfections in Solids	Account for the following: Schottky defects lower the density of related solids. Conductivity of silicon increases on doping it with phosphorus.
41	Calculations Involving Unit Cell Dimensions	(a) Why does presence of excess of lithium makes LiCl crystals pink? (b) A solid with cubic crystal is made of two elements P and Q. Atoms of Q are at the corners of the cube and P at the body-centre. What is the formula of the compound?
42	Classification of Crystalline Solids	Classify the following solids with appropriate reason: - (A) Argon (B) Sulphur dioxide
43	Close Packed Structures	Out of squre close packing hexagonal close packing which one is more stable and why in two dimensions.
44	Close Packed Structures	What is the relation between? - A). Total number of well packed particles, number of octahedral and number of tetrahedral voids in a unit cell. B). Edge length of (a) and radius of constituent particle in (r) body centered unit cell.
45	Imperfections in Solids	Account on the following: - A). ZnO on heating turn white to yellow. B). d-block elements show metal deficiency defect.
46	Imperfections in Solids	Analysis shows that a metal oxide has  the  empirical  formula  M0.98O1.00. Calculate the percentage of M2+ and M3+ ions in the crystal.
47	Imperfections in Solids	Explain how electrical neutrality is maintained in compounds showing Frenkel and Schottky defect.
48	Electrical Properties	In terms of band theory, what is the difference between a conductor, an insulator and a semi-conductor?
49	Electrical Properties	The electrical conductivity of a metal decreases with rise in temperature while that of a semi-conductor increases. Explain.
50	Magnetic Properties	What type of substances would make better permanent magnets, ferromagnetic or ferromagnetic? Why?
51	Calculations Involving Unit Cell Dimensions	In compound atoms of element Y forms ccp lattice and those of element X occupy 2/3rd of tetrahedral voids. What is the formula of the compound?
52	Amorphous and Crystalline Solids	Some of the very old glass objects appear slightly milky instead of being transparent.
53	Imperfections in Solids	Ionic solids which have an ionic vacancy due to metal excess defect develop colour explain with the help of a suitable example
54	Close Packed Structures	What is AB....AB....AB..... type of arrangement and ABC......ABC......ABC. type of arrangement. Write the coordination number for each.

 

SHORT ANSWER-II TYPE QUESTIONS (3 Marks)

 

S.No.	Topic-Concept Name	SA TYPE-II (3 Marks)
55	Electrical Properties	What is a semiconductor? Describe the two main types of semiconductors and explain mechanisms for their conduction
56	Imperfections in Solids	How would your account for the following? a. Frenkel defects are not found in alkali metal halides. b. Schottky defects lower the density of related solids. c. Impurity doped silicon is a semiconductor.
57	Magnetic Properties	Explain the following properties giving suitable examples: a. Ferromagnetism b. Para magnetism c. Ferrimagnetism
58	Calculations Involving Unit Cell Dimensions	Iron has a body-centered cubic unit cell with a cell edge of 286.65 pm. The density of iron is 7.87g cm–3. Use this information to calculate Avogadro’s number (At. mass of Fe = 56g  mol–11).
59	Calculations Involving Unit Cell Dimensions	The well-known mineral fluorite is chemically calcium fluoride. It is known that in one-unit cell of this mineral there are 4 Ca2+ ions and 8 F– ions and that Ca2+ ions are arranged in a fcc lattice. The F– ions fill all the tetrahedral holes in the face centred cubic lattice of Ca2+ ions. The edge of the unit cell is 5.46 × 10–8 cm in length. The density of the solid is 3.18 g cm–3. Use this information to calculate Avogadro's number (Molar mass of CaF2 = 78.08 g mol–1)
60	Calculations Involving Unit Cell Dimensions	The density of copper metal is 8.95 g cm -3. If the radius of copper atom is 127.8 pm, is the copper unit cell a simple cubic, a body-centered cubic or a face-centered cubic structure? (Given: At. mass of Cu=63.54 g mol -1 and NA = 6.022 × 1023 mol -1)
61	Calculations Involving Unit Cell Dimensions	Aluminium crystallizes in a cubic close-packed structure. Radius of the atom in the metal is 125 pm. (i) What is the length of the side of the unit cell? (ii) How many unit cells are there in 1 cm3 of aluminium?
62	Crystal Lattices and Unit Cells	Define: - a. Lattice point b. Crystal lattice c. Bravais lattice

Thermodynamics and Thermodynamic terms:

Thermodynamics

    ·       This term consists of Thermo means Heat/energy) and Dynamics means motion.

     ·       Thermodynamics is the branch of science which deals with the various forms of energy and their transformation during all physical and chemical processes.

but Chemical thermodynamics is the branch of thermodynamics which deals with the study of energy changes taking place in chemical processes.

 Advantages of thermodynamics:

    ·       It gives information about various thermodynamic laws.

    ·       It helps us to predict whether a given chemical reaction will take place or not under the given set of conditions.

    ·       It gives information about various energy changes.

Limitations of thermodynamics:

    ·       The lows of thermodynamics apply to the properties like temperature, pressure, volume, etc of matter in bulk but doesn't tell us anything about the individual properties of atoms or molecules.

    i.e., Thermodynamics deals with macroscopic system but not with microscopic system.

     ·       It tells us whether a given chemical reaction will take place or not under the given set of conditions but doesn't tell us anything about how and at what rate of the energy transformations are carried out. i.e., it does not tell about the rate of reaction.

Thermodynamic terms:

System: is defined as a specified part of the universe or specified portion of the matter which is under experimental investigation

Surrounding: is defined as the remaining part of the universe which is not the part of the system.

Universe = System + Surrounding

 Boundary: Anything which separates system and surrounding is called boundary. Boundary can be categorised into three types.

    a.       conducting or non-conducting nature of boundary.

    b.       Boundary can be rigid or non-rigid.

    c.       Boundary can be real or imaginary.

For example: A reaction is carried out in a test tube. The contents of test-tube constitute the system, test tube serves as boundary and anything which is outside the test-tube is called surroundings.

Type of systems:

 There are three types of systems

a). Open system: a system which can exchange energy as well as matter with the surrounding is called open system. The boundary is neither sealed nor insulated. Total mass will not remain constant. Example-Tea in open glass

 b). Closed system:

·       a system which can exchange energy but not matter with its surroundings is called closed system.

·       The boundary is sealed but not insulated.

·       Amount of the system will remain constant.

·       Example- Hot water in closed vessel, Glowing bulb, tube light.

c). Isolated system:

·       a system which can neither exchange mass nor energy with the surroundings is called an isolated system.

·       boundary is sealed and insulated. Universe can be considered as an isolated system. Example-Coffee in thermos-flask.

State of system-

     The state of the system is defined by their measurable properties like temperature, pressure, volume etc.

 If any of these properties change, state of the system is said to be changed.

State variables-

   Properties which define state of any system are called its state variables or thermodynamic variables or thermodynamic quantities

State Function:

·       Those state variables which depend only upon initial and final state of the system but doesn't depend upon the path or mechanism followed by the system to achieve final state are called state function.

·       State functions are denoted by capital letters. Ex. E, H, S, G, T, P, V etc

      Path function:

·       Properties of the system which depend upon the initial and final state of the system as well as the path or mechanism followed by the system to achieve final state are called path function.

·       Path functions are denoted by small letters. Example- Work (w), Heat(q).

Type of process-

      The state of a thermodynamic system can be changed by a process. These may be

a). Isothermal process- defined as a process which takes place at constant temperature.

b). Isobaric process- defined as a process which takes place at constant pressure.

c). Isochoric process- defined as a process which takes place at constant volume.

d). Adiabatic process- a process in which the system does not exchange heat with the surroundings is called adiabatic process. But The temperature pressure, volume of the system varies.

e). Irreversible process- A process which is not reversible is called an irreversible is called an irreversible is called an irreversible process.

In this process driving force is very different than the opposing force. Ex- all-natural process.

f). reversible process- proceeds infinitely slowly. In this process driving force is infinitesimally small difference than the opposing force.

g).Cyclic Process : When a system undergoes a number of different processes and finally returns to its initial state, it is termed as cyclic process. In cyclic process change in all state function will be zero. i.e., ΔE = 0, ΔH = 0, ΔP = 0, ΔT = 0

Thermodynamic properties:

the properties which arise from the bulk behaviour of matter are called macroscopic properties.it can be sub-divided into two types-

These are as

a). Intensive properties

 b). Extensive properties

S.no.	Intensive properties	Extensive properties
1	The properties of the system which do not depend upon the amount or size of matter present in system are called intensive properties.	The properties of the system which depend upon the amount or size of matter present in system are called extensive properties.
2	Example- Temperature, pressure, viscosity, surface tension, dielectric constant, molar properties (as mole fraction, molar volume, molar heat capacity), vapour pressure, Boiling point, freezing point, PH value, Cell potential etc.	Example- mass, volume, surface area, internal energy, enthalpy, entropy, free energy, heat capacity etc.

Internal energy:

Internal energy: We know that every substance passes some energy since its origin.

so the internal energy is the sum total of all the energies possessed by the system .

☝It is denoted by U.

☝It is a state function.

☝It is an extensive property.

☝U of the system may be changed when

    a) q passes or out of the system

    b) work is done on or by the system

    c)  matter enters or leaves the system

Change in Internal Energy by Doing Work-

Let us bring the change in the internal energy by doing work.

Let the initial state of the system is state A and Temperature TA 

Internal energy = UA

On doing’some mechanical work the new state is called state B and the temp. TB, internal energy of it UB It is found to be

           TB > TA

UB is the internal energy after change.ΔU = UB – UA

Change in Internal Energy by Transfer of Heat

Internal energy of a system can be changed by the transfer of heat from the surroundings to the system without doing work                                      

                                 ΔU = q

Where q is the heat absorbed by the system. It can be measured in terms of temperature difference.

q is +ve when heat is transferred from the surroundings to the system. 

q is -ve when heat is transferred from system to surroundings.

First law of thermodynamics-

When change of state is done both by doing work and transfer of heat.Then internal energy will be                                          ΔU = q + w

First law of thermodynamics

(Law of Conservation of Energy). It states that, energy can neither be created nor be destroyed. The energy of an isolated system is constant.

                                 ΔU = q + w.