Xam Idea Class 12 Chemistry Chapter 1 Solutions: The Solid State

Xam Idea Class 12 Chemistry Solutions Chapter 1-The Solid State is written by subject experts in a descriptive manner. It is an important study material for all you Class 12 students appearing for board exams. Our solutions for chemistry chapter 1 provide clear and precise answers to solid-state chemistry. These follow all the guidelines provided by CBSE and NCERT.

Our Xam Idea Solutions Class 12 Chemistry Solutions are divided into two major parts. The first part contains all the chapters of class 12 CBSE Chemistry Syllabus. These give you an idea regarding what to expect in the actual examination. The second part contains helpful question-answer tools, useful model test papers, sample question papers for the class twelve CBSE chemistry examination and NCERT questions that supplement the chapters in the first part of the book. In our solutions, all model question papers have been solved comprehensively and in a stepwise manner to help you learn efficiently.

Xam Idea Class 12 Chemistry Solutions Chapter 1 covers all the topics given in the first chapter of NCERT Chemistry Class 12 Book. From these solutions, you will be able to understand the general characteristics of matter in solid-state, how are solids classified, crystal lattice, types of the unit cell, types of solids packing, voids, doping and imperfections in solids.

Xam Idea Class 12 Chemistry Chapter 1 – The Solid State

Xam Idea Class 12 Chemistry Solutions Chapter 1-The Solid State covers all the important concepts of the unit. They help you gain an in-depth understanding of the different concepts. Some concepts covered in this chapter have been given below.


  • General Characteristics of Solid State


This part of the chapter tells you that there are three states of matter, namely solid, liquid and gas. Here you learn about the properties and specialities of the solid-state. The distinct properties of solids can be listed as follows 

(a) Solids have a definite shape, volume and mass 

(b) In solids, the intermolecular distance is less whereas intermolecular force is strong

(c) Solids are rigid and cannot be compressed 

(d) Solid particles have fixed positions in their lattice structure.


  • Amorphous and Crystalline Solids


This portion of the chapter teaches you that solids are divided into two types – amorphous and crystalline. Here you will learn that the word ‘amorphous’ means no form and in this type of solids, the particles are of indefinite shape and have short-range order, these are also known as supercooled or pseudo solids. Example of amorphous solids is Quartz glass. You will also learn that crystalline solids or true solids have a definite geometric shape and possess long-range order. These solids are isotropic and do not have definite heat of fusion. Sodium chloride is an example of a crystalline solid. The other types of solids are molecular solids, ionic solids and metallic solids. Xam Idea Class 12 Chemistry Solutions Chapter 1-The Solid State covers this topic very well.


  • Crystal Lattices and Unit Cells


This part of the chapter tells you that the smallest repeating unit of the crystal lattice which can be used to build up the whole crystal is known as a unit cell. It further tells you that crystal lattice is the definite three-dimensional arrangement of particles of a crystal in space and there are 14 such arrangements possible known by the general name of Bravais Lattices.

Then you learn about types of unit cells that are simple or primitive unit cells where particles are present at the corners of an imaginary cube only and centred unit cells like face-centred (fcc), body centred (bcc) and end centred unit cells. Next, you learn how to calculate the number of atoms in a unit cell. In Xam Idea Class 12 Chemistry Solutions Chapter 1-The Solid State, you come to know that simple cubic, fcc, bcc and end centred types of cells have 1, 4, 2 and 2 atoms per unit cell, respectively.


  • Close Packed Structures 


This portion of the chapter teaches you about the close packing of crystals and how they can be packed closely in one, two and three dimensions to give different types of structures. It further tells you about tetrahedral and octahedral voids developed in between the layers of constituent particles during three-dimensional packing. Hexagonal close packing (hcp) and cubic close packing (ccp) are the most efficient packing systems.

You also learn about calculating the formula of a compound and number of voids filled. You learn to calculate the packing efficiency of unit cells like hcp, ccp, bcc and simple cubic lattice structures. It is depicted as the percentage of total space filled by the particles and is known as packing efficiency. Packing efficiency of hcp and ccp packing is 74%, and in bcc and simple cubic lattice, it is 68% and 52.4 % respectively. Here, you learn how to do calculations involving unit cell dimensions. Xam Idea Class 12 Chemistry Solutions Chapter 1-The Solid State covers a number of numerical problems from this topic.


  • Imperfections in solid


This portion of the chapter tells you that the imperfections in crystalline solids are the anomalies in the structure known as a point (around a point in crystal) and line defects (in the whole row). Point defects can be of three types known as stoichiometric, impurity and non-stoichiometric defects. It further tells you that stoichiometric defect does not disturb the stoichiometry of crystals.

Vacancy and interstitial, the two basic types of defects can be shown by non-ionic solids and Frenkel, and Schottky defects are shown by ionic solids. Impurity defect is brought about by the presence of any impurity in the crystal. Metal excess and metal deficiency are the two types of non-stoichiometric defects. Xam Idea Class 12 Chemistry Solutions Chapter 1-The Solid State provides you with ample practice on the concept of crystal imperfections and defects.


  • Electrical Properties


This portion of the chapter tells you about the conduction of electricity in metals and semiconductors. It also tells you that properties of defects are utilized in making semiconductors for improved electrical properties of crystalline substances. This is done by doping impurities into a crystal to prepare p-type and n-type semiconductors.


  • Magnetic Properties


This part of the chapter tells you that most substances have some magnetic properties associated and, based on this, they can be divided into five categories – paramagnetic, diamagnetic, ferromagnetic, ferrimagnetic and antiferromagnetic. These properties are used in making the video, audio and recording related electronic gadgets. Xam Idea Class 12 Chemistry Solutions Chapter 1-The Solid State covers a variety of questions and answers on this important concept. 

Xam Idea Class 12 Chemistry Chapter 1 – Exercises

The questions asked in this chapter have been divided according to the marks into various sections of very short answer (VSA) questions, short answer (SA)questions, and long answer questions (LA) questions. Every chapter includes diversified questions based on remembering and understanding, higher-order thinking skills (HOTS), based on application and value-based questions. 

This chapter has 58 VSAQs which are based on concepts of types of solids, coordination number, stoichiometric and other crystal defects, doping and semiconductors, magnetic properties of solids, voids and types of unit cells. 

Further, there are 37 SAQs which are based on the concepts of tetrahedral and octahedral voids, various crystal lattices, conduction of silicon, semiconductors, numerical questions on the number of atoms per unit cell in a different type of unit cell. 

Finally, there are 7 LAQs which ask you to solve numerical questions, to tell differences and to identify magnetic properties. Our Xam Idea Class 12 Chemistry Solutions Chapter 1-The Solid State provides the best answers to all these questions.

After trying your hands on the above questions, you must solve the other questions given in part A such as important NCERT questions, exemplar questions and important questions of previous years’ examinations. Further, you should solve the latest CBSE sample papers, model question papers previous year’s examination papers given in part – B of the Xam Idea Class 12 Chemistry Solutions for a more holistic practice.

Benefits of Xam Idea Class 12 Chemistry Chapter 1 – The Solid State

Some of the major benefits of referring Xam Idea Class 12 Chemistry Chapter 1 – The Solid State are as follows –

  • They help you build a strong conceptual foundation of the molecules used in various ways in our day to day life.
  • These solutions give you tips and techniques to remember and correctly apply the concepts. 
  • Our methods of solving questions are unique, and they certainly help to solve all types of numerical questions from this chapter quickly and effectively.
  • They are a handy source of all the topics mentioned in this chapter for effective revision during exams. 
  • They give you an idea of the types of questions asked in various exams and ways to solve the same.
  • The solutions are framed in such a way that they make the learning process engaging, interactive and efficient.
  • They help you score well in your class 12 board exams specifically by answering doubts and making the concepts clear.