A TEXT BOOK OF

ENGINEERING CHEMISTRY - II FOR

SEMESTER - II F.E. DEGREE COURSES IN ENGINEERING (COMMON FOR ALL BRANCHES) (CODE - FEC203)

As Per Revised Syllabus of UNIVERSITY OF MUMBAI, MUMBAI

Choice Based Credit and Grading System w.e.f. Academic Year 2019-2020

Dr. (Mrs.) Trupti S. Paradkar

Associate Professor Dwarkadas J. Sanghvi College of Engineering Vile Parle (W), Mumbai - 400056

N6006

ENGINEERING CHEMISTRY - II

ISBN 978-93-89825-49-7

Second Edition : April 2022 © : Author The text of this publication, or any part thereof, should not be reproduced or transmitted in any form or stored in any computer storage system or device for distribution including photocopy, recording, taping or information retrieval system or reproduced on any disc, tape, perforated media or other information storage device etc., without the written permission of Authors with whom the rights are reserved. Breach of this condition is liable for legal action. Every effort has been made to avoid errors or omissions in this publication. In spite of this, errors may have crept in. Any mistake, error or discrepancy so noted and shall be brought to our notice shall be taken care of in the next edition. It is notified that neither the publisher nor the authors or seller shall be responsible for any damage or loss of action to any one, of any kind, in any manner, therefrom. The reader must cross check all the facts and contents with original Government notification or publications. Published By :

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PREFACE It gives me immense pleasure to present the first edition of the book on Engineering

Chemistry - II to the students of first year engineering. This book is prepared according to the new syllabus (2019) of University of Mumbai; which comes into effect from the academic year 2019-2020.

The syllabus has been meticulously followed throughout the book with emphasis on

minute details. The topics have been structured in order to develop the subject in a

logical sequence. The coverage of this book will definitely help students to understand and grasp the subject with ease.

Numerous solved problems including the ones from university examinations of past

years on different topics have been incorporated wherever applicable. This would help the students in solving a wide variety of problems.

At the end of every chapter there are ample unsolved problems for practice along

with answer keys. Review questions on theory are added along with references to the

appropriate sections from the book. University problems and theory questions of recent past are listed year wise under every chapter.

Any constructive suggestions for enhancing the utility of this book and for removing

errors that might have gone unnoticed will be gratefully acknowledged.

Author Dr. (Mrs.) Trupti S. Paradkar

ACKNOWLEDGEMENT I honestly acknowledge Shri Vile Parle Kelavani Mandal for providing the infrastructural facilities in the college. My thanks are also due to Principal Dr. Hari Vasudevan, Dwarkadas J. Sanghavi College of Engineering for his continued support and encouragement. I sincerely thank my friends for their suggestions, and well-wishers for their moral support while writing this book. I would like to express my deepest gratitude to Mr. Dineshbhai K. Furia and Mr. Pradeep K. Furia of M/s Nirali Prakashan. I am indeed thankful to Mr. Shashikant Patel for facilitating the coordination required for publishing this edition. I am also thankful to Mr. Paras Rambhia & Mr. Hardik Vira of Decent Typesetters for their excellent computer typesetting work. I am also grateful to my husband Mr. Sanjay Paradkar and loving daughter Owee for bearing with me throughout this exercise. Last but not the least, special thanks to my students for their overwhelming response to all my earlier books on Applied Chemistry & Engineering Chemistry I. Author Dr. (Mrs.) Trupti S. Paradkar

DEDICATED TO MY HUSBAND

SANJAY & LOVING DAUGHTER

OWEE

For their unconditional love and support

SYLLABUS Module 1 : Principles of Spectroscopy • •

Introduction : Principle of spectroscopy, Definition, Origin of spectrum, Classification of spectroscopy – atomic and molecular, selection rules. Table of relation between electromagnetic spectrum, types of spectroscopy and energy changes.

Module 2 : Applications of Spectroscopy • •

• • •

•

• • •

04 Hours

Introduction – Definition, significance Twelve Principles of Green chemistry, numerical on atom economy, Conventional and green synthesis of Adipic acid, Indigo, Carbaryl, Ibuprofen, Benzimidazole, Benzyl alcohol, % atom economy and their numericals. Green fuel – Biodiesel.

Module 6 : Fuels and Combustion • •

06 Hours

Definition, Mechanism of Corrosion – (I) Dry or Chemical Corrosion (i) Due to oxygen, (ii) Due to other gases. (II) Wet or Electrochemical corrosion – Mechanism (i) Evolution of hydrogen type, (ii) Absorption of oxygen. Types of Corrosion – Galvanic cell corrosion, Concentration cell corrosion (differential aeration principle), Pitting corrosion, Intergranular corrosion, Stress corrosion. Factors affecting the rate of corrosion – (i) Nature of metal, (ii) Nature of corroding environment. Methods of corrosion control – (I) Material selection and proper designing, (II) Cathodic protection – (i) Sacrificial anodic protection, (ii) Impressed current method, (III) Metallic coatings – only Cathodic coating (tinning) and anodic coatings (Galvanising)

Module 5 : Green Chemistry and Synthesis of Drugs • •

02 Hours

Introduction, concept of electrode potential, Nernst equation, types of electrochemical cells, concept of standard electrode with examples, electrochemical series, simple numericals.

Module 4 : Corrosion •

04 Hours

Emission spectroscopy – Principle, Instrumentation and applications (Flame Photometry) Introduction to florescence and phosphorescence, Jablonski diagram, application of fluorescence in medicine only.

Module 3 : Concept of Electrochemistry •

02 Hours

06 Hours

Definition, classification, characteristics of a good fuel, units of heat (no conversions). Calorific value – Definition, Gross or Higher calorific value & Net or lower calorific value, Dulong‘s formula & numerical for calculations of Gross and Net calorific values. Solid fuels – Analysis of coal – Proximate and Ultimate Analysis – numerical problems and significance. Liquid fuels – Petrol – Knocking, Octane number, Cetane number, Antiknocking agents, unleaded petrol, oxygenates (MTBE), catalytic converter. Combustion – Calculations for requirement of only oxygen and air (by weight and by volume only) for given solid & gaseous fuels.

TEACHING AND EXAMINATION SCHEME Course code FEC203

Course Name Engineering Chemistry-II

Course code

Course Name

FEC203

Engineering Chemistry-II

Teaching Scheme (Contact Hours) Theory Practical Tutorial 2

-

-

Theory Internal Assessment Test 2 Test 1 Average 15

15

15

Credits Assigned Tutorial Practical

Theory 2

-

-

Total 2

Examination Scheme End Sem. Exam.

Exam. Duration (in Hrs.)

Term work

Practical/ Oral

Total

60

2

-

-

75

ASSESSMENT Internal Assessment Test Assessment consists of two class tests of 15 marks each. The first class test is to be conducted when approx. 40% syllabus is completed and second class test when additional 35% syllabus is completed. Duration of each test shall be one hour. End Semester Examination In question paper weightage of each module will be proportional to number of respective lecture hours as mention in the syllabus. 1.

Question paper will comprise of 6 questions, each carrying 15 marks.

2.

Question number 1 will be compulsory and based on maximum contents of the syllabus.

3.

Remaining questions will be mixed in nature (for example, if Q.2 has part (a) from module 3 then part (b) will be from other than module 3).

4.

Total four questions need to be solved.

CONTENTS Chapter - 1

Principles of Spectroscopy

1.1 - 1.12

1.1 1.2

Introduction ..................................................................................................................................................1.1 Electromagnetic Radiation ......................................................................................................................1.2

1.4

Principles of Spectroscopy ......................................................................................................................1.6

1.3 1.5 1.6 1.7

1.8 1.9

Electromagnetic Spectrum ......................................................................................................................1.5 Types of Spectroscopy..............................................................................................................................1.7 Selection Rules.............................................................................................................................................1.7 Applications of Molecular Spectroscopy ...........................................................................................1.8

Types of Molecular Energies ..................................................................................................................1.8 Types of Molecular Spectroscopy ........................................................................................................1.9

1.10 Review Questions .................................................................................................................................... 1.11 Chapter - 2

Applications of Spectroscopy

2.1 - 2.10

2.1

Introduction of Flame Photometry ......................................................................................................2.1

2.3

Instrumentation of Flame Photometry ...............................................................................................2.2

2.2

2.4 2.5 2.6

Theory of Flame Photometry .................................................................................................................2.1 Working of Flame Photometer ..............................................................................................................2.3 Quantitative Estimation of Flame Photometry ................................................................................2.4

Interferences in Flame Photometry .....................................................................................................2.4

2.7

Applications of Flame Photometry ......................................................................................................2.4

2.9

Jablonski Diagram ......................................................................................................................................2.5

2.8

Advantages & Disadvantages of Flame Photometry ....................................................................2.5

2.10 Introduction to Fluorescence .................................................................................................................2.7

2.11 Introduction to Phosphorescence ........................................................................................................2.7 2.12 Applications of Fluorescence in Medicines ........................................................................................2.9

2.13 Review Questions .......................................................................................................................................2.9 Chapter - 3

Concept of Electrochemistry

3.1 - 3.16

3.1

Introduction ..................................................................................................................................................3.1

3.3

Electrode Potential .....................................................................................................................................3.4

3.2 3.4 3.5

3.6 3.7 3.8

Electro Chemical Cell .................................................................................................................................3.1

Reference Electrode ...................................................................................................................................3.6

Electro Chemical Series ............................................................................................................................3.8 Galvanic Series .......................................................................................................................................... 3.11 Nernst Equation ....................................................................................................................................... 3.13

Review Questions .................................................................................................................................... 3.15

Chapter - 4

Corrosion

4.1 - 4.52

4.1

Introduction ..................................................................................................................................................4.1

4.3

Theories of Corrosion................................................................................................................................4.3

4.2

4.4

Cause of Corrosion.....................................................................................................................................4.2 4.3.1 Dry or Chemical or Atmospheric Corrosion .........................................................................4.3 4.3.2 Wet Corrosion or Electrochemical Corrosion ......................................................................4.7

Types of Corrosion .................................................................................................................................. 4.12 4.4.1 Concentration Cell Corrosion .................................................................................................. 4.12

4.4.2 Galvanic or Bimetallic Corrosion ............................................................................................ 4.13

4.4.3 Pitting Corrosion .......................................................................................................................... 4.14 4.4.4 Stress Corrosion ........................................................................................................................... 4.16

4.5

4.6 4.7

4.8

4.9

4.4.5 Intergranular Corrosion ............................................................................................................. 4.18 Factors Affecting Rate of Corrosion ................................................................................................. 4.19 4.5.1 Nature of Metal ............................................................................................................................ 4.19

4.5.2 Nature of Environment .............................................................................................................. 4.22 Corrosion Control .................................................................................................................................... 4.24

Design and Material Selection............................................................................................................ 4.24 Cathodic Protection ................................................................................................................................ 4.27

4.8.1 Cathodic Protection by Galvanizing Coupling (By Sacrificial Anode) ..................... 4.28

4.8.2 Impressed Current Cathodic Protection ............................................................................. 4.29 Application of Protective Coating ..................................................................................................... 4.31

4.9.1 Metallic Coatings ......................................................................................................................... 4.31 4.9.2 Organic Coating ........................................................................................................................... 4.37

4.10 Review Questions .................................................................................................................................... 4.40 4.11 University Questions............................................................................................................................... 4.43

Chapter - 5

Green Chemistry and Synthesis of Drugs

5.1 - 5.30

5.1

Introduction ..................................................................................................................................................5.1

5.3

Basic Ideas in the Field of Green Chemistry Research..................................................................5.7

5.2

5.4 5.5

5.6

5.7

Basic Principles of Green Chemistry ....................................................................................................5.2

Atom Economy ......................................................................................................................................... 5.12

Industrial Applications of Green Chemistry................................................................................... 5.18

Review Questions .................................................................................................................................... 5.20 University Questions............................................................................................................................... 5.21

Chapter - 6

Fuels and Combustion

6.1 - 6.116

6.1

Introduction ..................................................................................................................................................6.1

6.3

Characteristics of a Good Fuel ...............................................................................................................6.2

6.2

6.4

Classification of Fuels ................................................................................................................................6.2

Calorific Value ..............................................................................................................................................6.3

6.4.1 Units of Heat .....................................................................................................................................6.3 6.4.2 Higher Calorific Value or Gross Calorific Value ...................................................................6.4

6.5

6.6

6.7 6.8

6.9

6.4.3 Net Calorific Value or Lower Calorific Value ........................................................................6.5

Theoretical Calculation of Calorific Value of Fuel ..........................................................................6.5

Analysis of Coal and its Significance ................................................................................................ 6.17 6.6.1 Proximate Analysis ...................................................................................................................... 6.18

6.6.2 Ultimate Analysis.......................................................................................................................... 6.25 Combustion ............................................................................................................................................... 6.42

Liquid Fuels ................................................................................................................................................ 6.87

Gasoline or Petrol .................................................................................................................................... 6.87 6.9.1 Unleaded Petrol and Catalytic Converter ........................................................................... 6.88

6.10 Knocking

................................................................................................................................................. 6.88

6.11 Octane Value ............................................................................................................................................. 6.90 6.12 Cetane Value ............................................................................................................................................. 6.92 6.13 Anti-Knocking Agent .............................................................................................................................. 6.95 6.14 Power Alcohol ........................................................................................................................................... 6.96

6.15 Review Questions .................................................................................................................................... 6.97

6.16 Unsolved Problems ................................................................................................................................. 6.99 6.17 University Questions.............................................................................................................................6.104 References

1

CHAPTER

1

PRINCIPLES OF SPECTROSCOPY SYLLABUS • • •

Introduction : Principle of spectroscopy, Definition, Origin of spectrum Classification of spectroscopy – atomic and molecular, selection rules Table of relation between electromagnetic spectrum, types of spectroscopy and energy changes

1.1 INTRODUCTION In recent years, spectroscopy has been used extensively in the analysis/structure determination of organic compounds. The classical techniques which were successful with macro quantities of organic compounds failed when the organic compounds under investigation were available in micro or semi micro amounts. Several types of spectroscopy have been applied to the study of such organic compounds. These spectroscopic techniques possess numerous merits over the classical techniques which are as follows. 1. They take much less time. 2. They require very small amounts of the compound being studied. 3. They are generally very fast and economical in the long run. 4. They are generally non-destructive. i.e. the compounds being studied remain unchanged during spectroscopic examination and can be reused for other tests, if required. 5. They are highly reliable in establishing the identity of two compounds. 6. They give information which is recorded in the form of a permanent chart generally in an automatic or semi-automatic manner. 1.1

F.E. Sem.-II Engineering Chemistry-II

1.2

Principles of Spectroscopy

1.2 ELECTROMAGNETIC RADIATION Electromagnetic radiation is a simple harmonic wave with the properties of a sine wave. It travels in a straight line unless it is refracted or reflected.

Fig. 1.1 : Electromagnetic radiation and its components Some important characteristics of electromagnetic radiations are as follows. 1. These radiations are produced by the oscillations of electric charge and magnetic field residing on this atom. The electric and magnetic components are mutually perpendicular to each other and are coplanar. 2. These are characterized by their wavelength or frequencies or wave numbers. 3. The energy carried by an electromagnetic radiation is directly proportional to its frequency. The emission or absorption of radiation is quantized and each quantum of radiation is called a photon. 4. All types of radiations travel with the same velocity and no medium is required for their propagation. They can travel through vacuum. 5. When visible light (a group of electromagnetic radiations) is passed through a prism, it is split up into seven colours which correspond to definite wavelengths. This phenomenon is called as dispersion. Thus, a group of electromagnetic radiations can be split up into various components for analysis. The energy changes within a molecule during absorption and emission of electromagnetic radiation are quantized. The energy changes in a molecule are specified using the terms of frequency, wavelength and wavenumber which are explained below. A. Wavelength : It is the distance between the two adjacent crests or troughs in a particular wave. It is denoted by the letter λ (lambda). It can be expressed in angstrom units (A°) or in millimicrons (mµ). 1 A° = 10–8 cm;

1mµ = 10–7 cm

F.E. Sem.-II Engineering Chemistry-II

1.3

Principles of Spectroscopy

Visible light constitutes waves ranging from 3800 A° (violet end) to 7600 A° (red end). Different colors of light have different values of their wavelengths. Human eye is sensitive only to this small visible range and fails to detect ultraviolet light (λ < 3800 A°) and infra-red radiations (λ > 7600 A°). Amplitude refers to the maximum height to which the wave oscillates and equals the height of the crest or depths of the troughs. It is measure of the radiant power of the radiation.

Fig. 1.2 : Illustration of wavelength and amplitude of a wave B. Frequency : It is defined as the number of waves which can pass through a point in one second. It is expressed as ν (nu) in cycles per second or in Hertz (Hz) where 1Hz = 1 cycle sec–1 1 Frequency α Wavelength Greater the wavelength, smaller is the frequency. c Frequency ν = λ where

c = Velocity of electromagnetic radiation

C. Wave number : The number of waves that exist over a specific distance (unit length) is called wave ― number. It is expressed as v . It is the reciprocal of wave length and is expressed in per cm. It is frequently used in infra-red technique. If the wavelength of a light radiation is known, the corresponding wave number can be calculated. ― 1 v= λ D. Energy : Energy of a wave of the particular radiation can also be calculated by the relation, c E = hν = h ⋅ λ

F.E. Sem.-II Engineering Chemistry-II

1.4

Principles of Spectroscopy

h = Plank’s constant = 6.626 × 10–27 erg sec. ν = Frequency of radiation in cycles sec–1 c = Velocity of electromagnetic radiation λ = Wavelength in centimeters When the frequency is high, energy is higher and wavelength is smaller. When the wavelength is large, energy is lower. NUMERICAL ON ELECTROMAGNETIC RADIATON 1. Calculate the energy associated with a radiation having wavelength 4000 A°. Give answer in kcal mole–1 and also in Kilo Jules mole–1. Solution : λ = 4000 A° = 4000 × 10–8 cm c E = h⋅ λ (6.628 × 10–27) × (2.998 × 10–10) = (4000 × 10–8) = 4.968 × 10–12 ergs 4.968 × 10–12 × 6.023 × 1023 = 4.18 × 1010 = 71.6 kcals mole–1 Also 1 kcal = 4.184 kJ ∴ E = 71.6 × 4.184 = 299.5 kJ mole–1 Ans. : E = 71.6 kcals mole–1 E = 299.5 kJ mole–1 2. The energy for a quantum of light is 4.97 × 10-19 J. What is the wavelength and frequency of this light? Solution : E = 4.97 × 10–19 J c E = h⋅ λ c ∴ λ = h⋅E (6.62 × 10–34) × (3 × 108) = (4.97 × 10–19) = 3.99 × 10–7 m

F.E. Sem.-II Engineering Chemistry-II

1.5

ν

=

c λ

ν

=

3 × 108 = 7.52 × 1014 Hz 3.99 × 10–7

Principles of Spectroscopy

Ans. : λ = 3.99 × 10–7 m ν = 7.52 × 1014 Hz 3. Calculate the energy of green light of wavelength 535 × 10–9 m. Solution : λ = 535 × 10–9 m c E = h⋅ λ (6.625 × 10–34) × (3 × 108) = (535 × 10–9) = 3.71× 10–19 J Ans. : E = 3.71× 10–19 J 1.3 ELECTROMAGNETIC SPECTRUM Many types of electromagnetic radiations extending from cosmic rays to radio waves are a part of an electromagnetic spectrum. It consists of an ordered organization of the different radiations according to their wavelengths and frequencies. This complete electromagnetic spectrum is shown in the Fig. 1.3. γRays 10-14

XRays 10-12

10-10

IRRays

UVRays 10-8

10-6

10-4

Radar

FM

10-2

1

Short wave

TV

102

Wavelength (meters)

Visible Light 400

500

600

700

800

Wavelength (nanometers)

Fig. 1.3 : Various regions of electromagnetic spectrum

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