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12085 – CHEMISTRY PART I ISBN 81-7450-648-9
Textbook for Class XII
First Edition ALL RIGHTS RESERVED
January 2007 Pausa 1928 q No part of this publication may be reproduced, stored in a retrieval system or
transmitted, in any form or by any means, electronic, mechanical, photocopying,
Reprinted recording or otherwise without the prior permission of the publisher.
November 2007, December 2008, q This book is sold subject to the condition that it shall not, by way of trade, be lent,
re-sold, hired out or otherwise disposed of without the publisher’s consent, in any
January 2010, January 2011, form of binding or cover other than that in which it is published.
January 2012, January 2013, q The correct price of this publication is the price printed on this page, Any revised
November 2013, December 2014, price indicated by a rubber stamp or by a sticker or by any other means is incorrect
and should be unacceptable.
December 2015, February 2017
February 2018, January 2019,
August 2019, March 2020,
July 2021, February 2022
OFFICES OF THE PUBLICATION
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Head, Publication : Anup Kumar Rajput
Division
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FOREWORD
The National Curriculum Framework (NCF), 2005 recommends that
children’s life at school must be linked to their life outside the school.
This principle marks a departure from the legacy of bookish learning
which continues to shape our system and causes a gap between the
school, home and community. The syllabi and textbooks developed on
the basis of NCF signify an attempt to implement this basic idea. They
also attempt to discourage rote learning and the maintenance of sharp
boundaries between different subject areas. We hope these measures
will take us significantly further in the direction of a child-centred system
of education outlined in the National Policy on Education (1986).
The success of this effort depends on the steps that school principals
and teachers will take to encourage children to reflect on their own
learning and to pursue imaginative activities and questions. We must
recognise that, given space, time and freedom, children generate new
knowledge by engaging with the information passed on to them by adults.
Treating the prescribed textbook as the sole basis of examination is one
of the key reasons why other resources and sites of learning are ignored.
Inculcating creativity and initiative is possible if we perceive and treat
children as participants in learning, not as receivers of a fixed body of
knowledge.
These aims imply considerable change in school routines and mode
of functioning. Flexibility in the daily time-table is as necessary as
rigour in implementing the annual calender so that the required number
of teaching days are actually devoted to teaching. The methods used for
teaching and evaluation will also determine how effective this textbook
proves for making children’s life at school a happy experience, rather
than a source of stress or boredom. Syllabus designers have tried to
address the problem of curricular burden by restructuring and
reorienting knowledge at different stages with greater consideration for
child psychology and the time available for teaching. The textbook
attempts to enhance this endeavour by giving higher priority and space
to opportunities for contemplation and wondering, discussion in small
groups, and activities requiring hands-on experience.
The National Council of Educational Research and Training (NCERT)
appreciates the hard work done by the textbook development committee
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responsible for this book. We wish to thank the Chairperson of the
advisory group in science and mathematics, Professor J.V. Narlikar and
the Chief Advisor for this book, Professor B. L. Khandelwal for guiding
the work of this committee. Several teachers contributed to the
development of this textbook; we are grateful to their principals for
making this possible. We are indebted to the institutions and
organisations which have generously permitted us to draw upon their
resources, material and personnel. As an organisation committed to systemic
reform and continuous improvement in the quality of its products, NCERT
welcomes comments and suggestions which will enable us to undertake further
revision and refinement.
Director
New Delhi National Council of Educational
20 November 2006 Research and Training
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RATIONALISATION OF CONTENT IN THE TEXTBOOKS
In view of the COVID-19 pandemic, it is imperative to reduce content
load on students. The National Education Policy 2020, also emphasises
reducing the content load and providing opportunities for experiential
learning with creative mindset. In this background, the NCERT has
undertaken the exercise to rationalise the textbooks across all classes.
Learning Outcomes already developed by the NCERT across classes
have been taken into consideration in this exercise.
Contents of the textbooks have been rationalised in view of the following:
• Overlapping with similar content included in other subject areas in
the same class
• Similar content included in the lower or higher class in the same
subject
• Difficulty level
• Content, which is easily accessible to students without much
interventions from teachers and can be learned by children through
self-learning or peer-learning
• Content, which is irrelevant in the present context
This present edition, is a reformatted version after carrying out the
changes given above.
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vi
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PREFACE
Chemistry has made a profound impact on the society. It is intimately linked
to the well-being of human kind. The rate of advancements in chemistry is so
high that curriculum developers continuously look for strategies to cope with
these advancements. Also, the students have to be inspired to be the future
leaders who would make fundamental contributions. The present textbook is
a sincere effort in this direction.
The structure of the textbook, presented in two parts, comprises of sixteen
Units. Although the titles of various Units indicate a sort of
compartmentalisation into physical, inorganic and organic chemistry, readers
will find that these sub-disciplines have been intermingled, at least to a certain
extent, to have a unified approach to the subject. The approach of presentation
of the subject matter discourages students from rote memorisation. The subject
has in fact, been organised around the laws and principles of chemistry. As
students master these laws and principles, they will soon get to the point
where they can predict much of what will come.
Efforts have been directed towards making the subject stimulating and
exciting by references to the historical developments and its usefulness to our
lives, wherever appropriate. The text is well illustrated with examples from
surrounding environment to facilitate grasping of the qualitative and
quantitative aspects of the concept easily. Physical data are given in SI units
throughout the book to make comparison of various properties easier. IUPAC
system of nomenclature has been followed along with the common system.
Structural formulae of chemical compounds showing functional/coordinating
groups in different colours are drawn using electronic system. Each Unit has
a good number of examples, as illustrations, with their solutions and some
intext questions, the answers of some of which are given at the end of the Unit.
The end of Unit exercises are designed to apply important principles and
provoke thinking process to solve them. Answers of some of these exercises
are given at the end of the book.
A variety of materials, e.g., biographical sketches of some scientists,
additional information related to a particular topic, etc., is given in boxes with
a deep yellow coloured bar. This boxed material with a 'deep yellow bar' is to
bring additional life to the topic. However, it is non-evaluative. The structures
of some of the more complex compounds incorporated in the book are for
understanding their chemistry. As their reproduction would lead to
memorisation, it is also a non-evaluative portion of the text.
The information part has been significantly reduced and, wherever possible,
it has been substantiated with facts. However, it is necessary for students to
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be aware of commercially important chemicals, their process of manufacture
and sources of raw materials. This leads to descriptive material in the book.
Attempts have been made to make descriptions of such compounds interesting
by considering their structures and reactivity. Thermodynamics, kinetics and
electrochemical aspects have been applied to chemical reactions which should
be beneficial to students for understanding why a particular reaction happened
and why a particular property is exhibited by the product. There is currently
great awareness of environmental and energy issues which are directly related
to chemistry. Such issues have been highlighted and dealt with at appropriate
places in the book.
A team of experts constituted by the NCERT has developed the manuscript
of the book. It gives me great pleasure to acknowledge the valuable contribution
of all the members of this team. I also acknowledge the valuable and relentless
contribution of the editors in bringing the book to the present shape. I also
acknowledge with thanks the dedicated efforts and valuable contribution of
Professor Brahm Parkash, who not only coordinated the entire programme
but also actively involved in writing and editing of this book. Thanks are also
due to the participating teachers and subject experts of the review workshop
for their contribution, which has helped us to make the book learner friendly.
Also, I thank the technical and administrative staff of the NCERT for their
support in the entire process.
The team of this textbook development programme hopes that the book
stimulates its readers and makes them feel the excitement and fascination for
this subject. Efforts have been made to bring out this book error-free.
Nevertheless, it is recognised that in such a book of complexity, there could
inevitably be occasional errors. It will always be a pleasure to hear about
them from readers to take necessary steps to rectify them.
B.L. KHANDELWAL
viii
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Elements, their Atomic Number and Molar Mass
TEXTBOOK DEVELOPMENT COMMITTEE
CHAIRMAN, ADVISORY GROUP FOR TEXTBOOKS IN SCIENCE AND MATHEMATICS
J.V. Narlikar, Professor Emeritus, Chairman, Advisory Committee, Inter
University Centre for Astronomy and Astrophysics (IUCAA), Ganeshkhind,
Pune University Campus, Pune
CHIEF ADVISOR
B.L. Khandelwal, Professor, Director, Disha Institute of Management and
Technology, Raipur, Chhattisgarh. Formerly Chairman, Department of
Chemistry, Indian Institute of Technology, New Delhi
MEMBERS
A.S. Brar, Professor, Department of Chemistry, Indian Institute of Technology,
New Delhi
A.Q. Contractor, Professor, Department of Chemistry, Indian Institute of
Technology, Powai, Mumbai
Alka Mehrotra, Reader, DESM, NCERT, New Delhi
Anjni Koul, Lecturer, DESM, NCERT, New Delhi
Brahm Parkash, Professor, DESM, NCERT, New Delhi
I.P. Agarwal, Professor, DESM, Regional Institute of Education, NCERT,
Bhopal, M.P.
K.K. Arora, Reader, Department of Chemistry, Zakir Hussain College, University
of Delhi, New Delhi
K.N. Upadhayaya, Head (Retired), Department of Chemistry, Ramjas College,
Delhi University, Delhi
Kavita Sharma, Lecturer, DEE, NCERT, New Delhi
M.P. Mahajan, Professor, Department of Chemistry, Guru Nanak Dev
University, Amritsar, Punjab
M.L. Agarwal, Principal (Retired), Kendriya Vidyalaya, Jaipur, Rajasthan
Puran Chand, Professor, Joint Director (Retired), CIET, NCERT, New Delhi
R.A. Verma, Vice Principal, Shaheed Basant Kumar Biswas Sarvodaya
Vidyalaya, Civil Lines, New Delhi
R.K. Verma, Professor, Department of Chemistry, Magadh University, Bihar
R.K. Prashar, Lecturer, DESM, NCERT, New Delhi
R.S. Sindhu, Professor, DESM, NCERT, New Delhi
S.K. Gupta, Reader, School of Studies in Chemistry, Jiwaji University,
Gwalior, M.P.
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S.K. Dogra, Professor, Dr B.R. Ambedkar Centre for Biomedical Research,
University of Delhi, Delhi
Sarabjeet Sachdeva, PGT, (Chemistry), St. Columbas School, New Delhi
S. Badhwar, Lecturer, The Daly College, Indore, M.P.
V.N. Pathak, Professor, Department of Chemistry, University of Rajasthan,
Jaipur, Rajasthan
Vijay Sarda, Reader, Department of Chemistry, Zakir Hussain College,
University of Delhi, New Delhi
V.K. Verma, Professor, (Retired), Institute of Technology, Banaras Hindu
University, Varanasi, U.P.
V.P. Gupta, Professor, DESM, Regional Institute of Education, NCERT, Bhopal,
M.P.
EDITORIAL COMMITTEE
B.L. Khandelwal
Brahm Parkash
K.N. Upadhayaya
K.K. Arora
R.S. Sindhu
Vijay Sarda
MEMBER-COORDINATOR
Brahm Parkash, Professor, DESM, NCERT, New Delhi
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ACKNOWLEDGEMENTS
The National Council of Educational Research and Training (NCERT) gratefully
acknowledges the valuable contributions of the individuals and organisations
involved in the development of Chemistry textbook for Class XII. The
acknowledgements are also due to the following practicing teachers and subject
experts for reviewing the draft manuscript and giving useful suggestions for
its improvement in a workshop: Dr D.S. Rawat, Department of Chemistry,
University of Delhi, Delhi; Dr Mahendra Nath, Reader, Chemistry Department,
University of Delhi, Delhi; Dr Sulekh Chandra, Reader, Zakir Hussain College,
New Delhi; Ms Ameeta K., PGT (Chemistry), Vidyalaya No. 3, Patiala Cantt
(Pb.); Dr G.T. Bhandge, Professor and Head, DESM, Regional Institute of
Education, Mysore; Dr Neeti Mishra, Senior Lecturer, Department of Chemistry,
Acharya Narendra Dev College, New Delhi; Dr. S.P.S. Mehta, Department of
Chemistry, Kumaun University, Nainital (UA); Dr N.V.S. Naidu, Assistant
Professor (Chemistry), SVU College of Mathematics and Physical Sciences,
S.V. University, Tirupati (A.P.); Dr A.C. Handa, Hindu College, Delhi University,
Delhi; Dr A.K. Vashishtha, G.B.S.S.S. Jafrabad, Delhi; Dr Charanjit Kaur, Head,
Department of Chemistry, Sri Sathya Sai College for Women, Bhopal, P.O.
Habibganj; Ms Alka Sharma, PGT (Chemistry), S.L.S. DAV Public School,
Mausam Vihar, Delhi; Dr H.H. Tripathy, Reader (Retired), Regional Institute
of Education, Bhubaneswar; Shri C.B. Singh, PGT (Chemistry), Kendriya
Vidyalaya No. 2, Delhi Cantt, Delhi; Dr Neeti Mishra and Dr Sunita Hooda,
Acharya Narendra Dev College, Delhi University, New Delhi.
The Council also thanks the Members of Editorial Committee for their
unrelenting efforts in editing the manuscript and bringing it to the
present shape.
The Council also acknowledges the contribution of Shri Vijay Singh,
Shri Narender Kr. Verma, DTP Operator; Dr K.T. Chitralekha, Copy Editor;
Shri Abhimanyu Mohanty, Proof Reader ; Shri Deepak Kapoor, Incharge,
Computer Station in shaping this book.
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CONTENTS
FOREWORD iii
RATIONALISATION OF CONTENT IN THE TEXTBOOKS v
PREFACE vii
Unit 1 Solutions 1
1.1 Types of Solutions 1
1.2 Expressing Concentration of Solutions 2
1.3 Solubility 5
1.4 Vapour Pressure of Liquid Solutions 9
1.5 Ideal and Non-ideal Solutions 13
1.6 Colligative Properties and Determination of Molar Mass 15
1.7 Abnormal Molar Masses 23
Unit 2 Electrochemistry 31
2.1 Electrochemical Cells 32
2.2 Galvanic Cells 33
2.3 Nernst Equation 36
2.4 Conductance of Electrolytic Solutions 41
2.5 Electrolytic Cells and Electrolysis 51
2.6 Batteries 54
2.7 Fuel Cells 56
2.8 Corrosion 57
Unit 3 Chemical Kinetics 61
3.1 Rate of a Chemical Reaction 62
3.2 Factors Influencing Rate of a Reaction 66
3.3 Integrated Rate Equations 71
3.4 Temperature Dependence of the Rate of a Reaction 78
3.5 Collision Theory of Chemical Reactions 82
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Unit 4 The d-and f-Block Elements 89
4.1 Position in the Periodic Table 90
4.2 Electronic Configurations of the d-Block Elements 90
4.3 General Properties of the Transition Elements (d-Block) 92
4.4 Some Important Compounds of Transition Elements 105
4.5 The Lanthanoids 108
4.6 The Actinoids 111
4.7 Some Applications of d- and f-Block Elements 113
Unit 5 Coordination Compounds 118
5.1 Werner's Theory of Coordination Compounds 118
5.2 Definitions of Some Important Terms Pertaining to 121
Coordination Compounds
5.3 Nomenclature of Coordination Compounds 122
5.4 Isomerism in Coordination Compounds 125
5.5 Bonding in Coordination Compounds 128
5.6 Bonding in Metal Carbonyls 135
5.7 Importance and Applications of Coordination 136
Compounds
Appendices 141
Answers to Some Questions in Exercises 154
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