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NCERT Solutions for Class 12 Chemistry Chemistry I Chapter 1 The Solid State

NCERT Solution For Class 12 Chemistry Chemistry I

The Solid State Here is the CBSE Chemistry Chapter 1 for Class 12 students. Summary and detailed explanation of the lesson, including the definitions of difficult words. All of the exercises and questions and answers from the lesson's back end have been completed. NCERT Solutions for Class 12 Chemistry The Solid State Chapter 1 NCERT Solutions for Class 12 Chemistry The Solid State Chapter 1 The following is a summary in Hindi and English for the academic year 2024-25. You can save these solutions to your computer or use the Class 12 Chemistry.

Question 1

NCERT Solutions for Class 12 Chemistry Chemistry I Chapter 1 The Solid State

NCERT Solution For Class 12 Chemistry Chemistry I

Why are solids rigid?

Why do solids have a definite volume?

Classify the following as amorphous or crystalline solids: Polyurethane, naphthalene, benzoic acid, teflon, potassium nitrate, cellophane, polyvinyl chloride, fibre glass, copper.

Why is glass considred a super-cooled liquid?

Refractive index of a solid is observed to have the same value along all directions. Comment on the nature of this solid. Would it show clevage property?

Classify the following solids in different categories based on the nature of intermolecular forces operating in them: Potassium sulphate, tin, benzene, urea, ammonia, water, zinc sulphate, graphite, rubidium, argon, silicon carbide.

Solid A is a very hard, electrical insulator in solid as well as in molten state and melts at extremely high temperature. What type of solid is it?

Ionic solids conduct electricity in liquid state but not in solid state. Explain.

What type of solids are electrical conductors, malleable and ductile?

Give the significance of a 'lattice point'.

Name the parameters that characterize a unit cell.

Distinguish between Hexagonal and monoclinic unit cells.

Distinguish between Face-centred and end-centred unit cells.

Explain how much portion of an atom located at (i) corner and (ii) body-centre of a cubic unit cell is part of its neighbouring unit cell.

What is the two-dimensional coordination number of a molecule in square close packed layer ?

A compound forms hexagonal closed-packed structure. What is the total number of voids in 0.5 mol of it? How many of these are tetrahedral voids?

A compound is formed by two elements M and N. The element N forms ccp and atoms of M occupy 1/3 of tetrahedral voids. What is the formula of the compound?

Which of the following lattices has the highest packing efficiency: simple cubic body-centred cubichexagonal close packed lattice

An element with molar mass 2.7 x 10–2 kg mol–1 form a cubic unit cell with edge length 405 pm. If its density is 2.7 x 103 kg m–3. What is the nature of the cubic unit cell?

What type of defect can arise when a solid is heated? Which physical property is affected by it and in what way?

What type of stoichiometric defect is shown by (i) ZnS, (ii) AgBr (iii) KCl

Explain how vacancies are introduced in an ionic solid when a cation of higher valence is added as an impurity in it.

Ionic solids, which have anionic vacancies due to metal excess defect, develop colour. Explain with the help of a suitale example.

A group 14 element is to be converted into N-type semi-conductor by doping it with a suitable impurity. To which group should this impurity belong?

What type of substances would make better permanent magnets, ferromagnetic or ferrimagnetic, justify your answer.

how many the number of tetrahedral and octahedral voids are present in a cubic close packed structure of A spheres?

What would be the number of tetrahedral and octahedral voids,In a face centred cubic unit cell (i.e., ccp structure) 4 atoms/ions are present?

What type of point defect in a crystal of zinc sulphate?

A cubic solid is made of two elements Y and Z. Atoms of Z are at the corners of the cube and Y at the body centre. What is the formula of the compound?

MgO has rock salt type structure. What is the co-ordination number of each ion?

Thallium chloride exists in Cs CI type lattice. What are the co-ordination number of TI and Cl– ions?

What is the effect of pressure on NaCl type crystals?

In a crystal of zinc sulphide, zinc occupies tetrahedral voids. What is the coordination number of zinc?

Why is potassium chloride sometimes violet instead of pure white?

When high temperature is given to ferromagnetic substance what effect can be obtain ?

For hcp crystal structure of an element What is the maximum possible coordination number ?

How many atoms can be assigned to its unit cell if an element forms (i) a body centred cubic cell and (ii) a face centred cubic cell?

How many Ca+ ions occupy second nearest neighbour locations to a central Cs+ ion in caesium chloride crystal?

How many Na+ ions occupy second nearest neighbour locations of a Na+ ion in the structure of sodium chloride crystals?

Why FeO is non-stoichiometric with the formula Fe0.95 O explain?

Define non-stiochiometry defect in crystals?

What is the arrangement of Zn2+ and S2– ions in Zinc blende (ZnS) crystal structure?

explain the effect of Frenkel structural defect on the electrical conductance of a crystalline solid?

An ionic compound AB2 possess CaF2 type crystal structure. What the co-ordination number of A2+ and B– ions in crystal of AB2 explain.

What kind point defect lowers the density of a crystal?

What do you mean by ‘point defects' in crystals?

Define dislocation in crystals.

Explain the term ‘dislocations’ in relation to crystals?

Why does zinc oxide exhibit enhanced electrical conductivity on heating?

In a body centred unit cell, one of the diagonals contains two extra atoms. Find the number of atoms present per unit cell?

An element occurs in the bcc structure. How many atoms are present in its unit cell explain ?

What is the number of atoms per unit cell in a body centred cubic structure?

What are lattice defects imperfection?

what is Frenkel defect.Why is Frenkel defect found in AgCl ?

What type of void are developed in hexagonal close packing?

What is the co-ordination number of an octahedral void?

Give two exampls of the compounds that exhibit Schottky defect.

What are interstitials in a crystal?

What will happen if NaCl crystal is subjected to high pressure?

What is unit cell.

For tetrahedral co-ordination, what should be the range of radius ratio (r+/r–) value?

What type of structure possessed by a unit cell of CsCl.

What is the effect of increasing temperature on the conductivity of semi-conductors?

Define radius ratio. What is the ideal value for a tetrahedral void?

How in the crystal of zinc sulphide, zinc occupies tetrahedral voids. What is the coordination number of zinc?

What is point defects in solids.

What type of compounds exhibit Schottky defect?

The unit cell of a substance has cation A+ at the corners of the unit cell and anions B- the centre. What is the simplest formula of the the substance?

What is the co-ordination number of each ion in Na2O.

Why is an ionic crystal of NaCl a nonconductor explain?

What causes the conduction of electricity by semi-conductors?

What may be the difference between phosphorus doped and gallium doped semiconductors?

What are non-stoichiometric compounds?

In which compound Schottky and Frenkel defects are present together?

What is the percentage of free space in a body centred cubic crystal?

Give one example of anti ferroelectric solid and one example of ferroelectric solid.

What happens when CdCl2 is added to AgCl?

Name the solid substance in which cations occupy all the tetrahedral voids.

Classify the following solids in different categories based on the nature of intermolecular forces operating in them:
Potassium sulphate, tin, benzene, urea, ammonia, water, zinc
sulphate, graphite, rubidium, argon, silicon carbide.

Which of the following lattices has the highest packing efficiency:
simple cubic
body-centred cubic
hexagonal close packed lattice

An element with molar mass 2.7 x 10^–2kg mol^–1 form a cubic unit cell with edge length 405 pm. If its density is 2.7 x 10³ kg m^–3. What is the nature of the cubic unit cell?

What type of stoichiometric defect is shown by
(i) ZnS, (ii) AgBr (iii) KCl

Thallium chloride exists in Cs CI type lattice. What are the co-ordination number of TI and Cl^– ions?

How many Ca⁺ ions occupy second nearest neighbour locations to a central Cs⁺ ion in caesium chloride crystal?

How many Na⁺ ions occupy second nearest neighbour locations of a Na⁺ ion in the structure of sodium chloride crystals?

Why FeO is non-stoichiometric with the formula Fe_0.95 O explain?

What is the arrangement of Zn²⁺ and S^2– ions in Zinc blende (ZnS) crystal structure?

An ionic compound AB₂ possess CaF₂type crystal structure. What the co-ordination number of A²⁺ and B^– ions in crystal of AB₂ explain.

For tetrahedral co-ordination, what should be the range of radius ratio (r⁺/r^–) value?

The unit cell of a substance has cation A⁺ at the corners of the unit cell and anions B^- the centre. What is the simplest formula of the the substance?

What is the co-ordination number of each ion in Na₂O.

What happens when CdCl₂ is added to AgCl?

How many lattice points are there in one unit cell of each of the following lattice?
(a) face centred cubic
(b) face centred tetragonal
(c) body centred cubic

Agl crystallises in cubic close packed ZnS structure. What fraction of tetrahedral sites are occupied by Ag⁺ ions?

Classify each of the following solids as ionic, metallic, molecular, network (covalent) or amorphous:

(i) Tetra phosphorous decoxide (P₄O₁₀)

(ii) Ammonium phosphate (NH₄)₃PO₄

(iii) SiC

(iv) I₂

(v) P₄

(vi) Plastic

(vii) Graphite

(viii) Brass

(ix) Rb

(x) LiBr

(xi) Si

What is meant by the term ‘coordination number’?

(ii) What is the coordination number of atoms:

(a) in a cubic close-packed structure?

(b) in a body-centred cubic structure?

What is the co-ordination number of atoms:
(i) in a cubic close packed structure?
(ii) in a body centred cubic structure?

How will you distinguish between the following pairs of terms:
Hexagonal close-packing and cubic close-packing?

How will you distinguish between the following pairs of terms:
Crystal lattice and unit cell?

How will you distinguish between the following pairs of terms:
Tetrahedral void and octahedral void?

How many lattice points are there in one unit cell of each of the following lattice?
(i) face centered cubic
(ii) face centered tetragonal
(iii) body centered.

Non-stoichiometric cuprous oxide, Cu₂O can be prepared in laboratory. In this oxide, copper to oxygen ratio is slightly less than 2 :1. Can you account for the fact that this substance is a p-type semi-conductor ?

Classify each of the following as being either a p-type or an n-type semi conducor:
(i) Ge doped with In
(ii) B doped with Si.

Explain the following terms with suitable examples:
'Schottky defect'

Explain the following term with suitable examples:
'Frenkel defect'

Explain the following term with suitable examples:
'Interstitials'.

Explain the following term with suitable examples:
'F-centres'.

How would you account for the following:
Frenkel defects are not found in alkali metal halides.

How would you account for the following:
Schottky defects lower the density of related solids.

How would you account for the following:
Impurity doped silicon is a semiconductor.

Silver crystallises in an fcc lattice. The edge length of its unit cell is 4.077 x 10^–8 cm and its density is 10.5 g cm^-3. Calculate on this basis the atomic mass of silver. (N_A= 6.02 x 10²³ mol^–1).

Niobium crystallises in body centered cubic structure. If density is 8.55 g cm^–3, calculate atomic radius of niobium using its atomic mass 93 u.

Copper crystallizes into a fcc lattice with edge length 3.61 x 10^–8 cm. Show that the calculated density is in agreement with its measured value of 8.92 g cm^–3.

Analysis shows that nickel oxide has formula Ni 0.98 O_1.00 What fractions of Nickel exist as Ni²⁺ and Ni³⁺ ions?

Aluminium crystallizes in a cubic close-packed structure. Its metallic radius is 125 pm.
(a) What is the length of the side of the unit cell?
(b) How many unit cells are there in 1.00 cm³ of aluminium?