TEXTBOOK OF QUANTITATIVE CHEMICAL G. H. JEFFERY J. BASSETT J. MENDHAM R C. DENNEY TEXTBOOK OF QUANTITATIVE CHEMICAL ANALYSIS FIFTH EDITION Revised by the following members of The School of Chemistry, Thames Polytechnic, London G H Jeffery, B Sc, Ph D, C Chem, F R S C Former Principal Lecturer and Deputy Head of the School of Chemistry J Bassett, M Sc, C Chem, F R S C Former Senior Lecturer in Inorganic Chemistry J Mendham, M Sc, C Chem, M R S C Principal Lecturer in Analytical Chemistry R C Denney, B Sc, Ph D, C Chem, F R S C, M B 1 M Principal Lecturer in Organic Chemistry . .n Longman iii Scientific & Technical w Copublished in the United States with John Wiley & Sons, Inc., New York Longman Scientific & Technical Longman Group UK Limited Longman House, Burnt Mill, Harlow Essex CM20 2JE, England and Associated Companies throughout the world Copublished in the United Srates with John Wiley and Sons Inc, 605 Third Avenue, New York NY 10158 O Longman Group UK Limited 1978, 1989 All rights reserved; no part of the publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of the Publishers, or a licence permitting restricted copying in the United Kingdom issued by the Copyright Licensing Agency Ltd, 33-34 Alfred Place, London WClE 7DP. First published in 1939 New impressions 1941, 1942, 1943, 1944, 1945, 1946, 1947, 1948 Second edition 1951 New impressions 1953, 1955, 1957, 1958, 1959, 1960 Third edition 1961 (published under the title A Text-book of Quantitative lnorganic Analysis lncluding Elementary Instrumrntal Analysis) New impressions 1962, 1964, 1968, 1969, 1971, 1974, 1975 Fourth edition 1978 New impressions 1979, 1981, 1983, 1985, 1986, 1987 Fifth edition 1989 British Library Cataloguing in Publication Data Vogel, Arthur Israel Vogel's textbook of quantitative chemical analysis. - 5th ed. 1. Quantitative analysis 1. Title II. Jeffery, G. H. 545 ISBN 0-582-Wb93-? Library of Congress Cataloguing in Publication Data Vogel, Arthur Israel [Textbook of quantitative chemical analysis] Vogel's textbook of quantitative chemical analysis. - 5th ed./ revised by ... G. H. Jeffery ... [et al.] p. cm. Rev. ed. of: Vogel's textbook of quantitative inorganic analysis. 4th ed. 1978. Includes bibliographies and index. ISBN 0-470-2151 7-8 1. Chemistry, Analytic-Quantitative. 2. Chemistry, Inorganic. 1. Jeffery, G. H. 1909- . II. Vogel, Arthur Israel. Vogel's textbook of quantitative inorganic analysis. III. Title. QD101.2.V63 1989 545-dc20 89- 12296 CIP Set in 1011 1p t Lasercomp Times New Roman Printed in Great Britain by Bath Press, Avon CONTENTS PART A FUNDAMENTALS OF QUANTITATIVE CHEMICAL ANALYSIS 1 CHAPTER 1 INTRODUCTION 3 1.1 Chemical analysis 3 1.2 Applications of chemical analysis 3 1.3 Sampling 4 1.4 Types of analysis 5 1.5 Use of literature 6 1.6 Common techniques 7 1.7 Instrumental methods 8 1.8 Other techniques 9 1.9 Factors affecting the choice of analytical methods 10 1.10 Interferences 12 1.11 Data acquisition and treatment 13 1.12 Summary 14 CHAPTER 2 FUNDAMENTAL THEORETICAL PRINCIPLES OF REACTIONS IN SOLUTION 15 2.1 Chemical equilibrium 15 2.2 The law of mass action 16 2.3 Factors affecting chemical reactions in solution 18 2.4 Electrolytic dissociation 19 2.5 Activity and activity coefficient 23 2.6 Solubility product 24 2.7 Quantitative effects of a common ion 26 2.8 Fractional precipitation 28 2.9 Effect of acids on the solubility of a precipitate 29 2.10 Effect of temperature on the solubility of a precipitate 30 2.11 Effect of the solvent on the solubility of a precipitate 30 2.12 Acid-base equilibria in water 31 2.13 Strengths of acids and bases 31 CONTENTS 2.14 Dissociation of polyprotic acids 33 2.15 Common-ion effect 34 2.16 The ionic product of water 36 2.17 The hydrogen ion exponent 38 2.18 The hydrolysis of salts 40 2.19 Hydrolysis constant and degree of hydrolysis 42 2.20 Buffer solutions 46 2.21 Complex ions 49 2.22 Complexation 51 2.23 Stability of complexes 52 2.24 Metal ion buffers 53 2.25 Factors influencing the stability of complexes 53 2.26 Complexones 55 2.27 Stability constants of EDTA complexes 58 2.28 Electrode potentials 60 2.29 Concentration cells 63 2.30 Calculation of the e.m.f. of a voltaic ce11 64 2.31 Oxidation-reduction cells 64 2.32 Calculation of the standard reduction potential 65 2.33 Equilibrium constants of oxidation-reduction reactions 67 CHAPTER 3 COMMON APPARATUS AND BASIC TECHNIQUES 71 3.1 Introduction 71 BALANCES 3.2 The analytical balance 72 3.3 Other balances 74 3.4 Weights, reference masses 75 3.5 Care and use of analytical balances 75 3.6 Errors in weighing 76 GRADUATED GLASSWARE 3.7 Units of volume 78 3.8 Graduated apparatus 79 3.9 Temperature standard 80 3.10 Graduated flasks 81 3.11 Pipettes 81 3.12 Burettes 84 3.13 Weight burettes 86 3.14 Piston burettes 87 3.15 Graduated (measuring) cylinders 87 3.16 Calibration of volumetric apparatus 87 WATER FOR LABORATORY USE 3.17 Purified water 89 3.18 Wash bottles 91 GENERAL APPARATUS 3.19 Glassware, ceramics, plastic ware 92 CONTENTS 3.20 Meta1 apparatus 93 3.21 Heating apparatus 97 3.22 Desiccators and dry boxes 98 3.23 Stirring apparatus 101 3.24 Filtration apparatus 102 3.25 Weighing bottles 104 REAGENTS AND STANDARD SOLUTIONS 3.26 Reagents 104 3.27 Purification of substances 105 3.28 Preparation and storage of standard solutions 107 SOME BASIC TECHNIQUES 3.29 Preparation of the substance for analysis 109 3.30 Weighing the sample 110 3.31 Solution of the sample 110 3.32 Precipitation 11 5 3.33 Filtration 115 3.34 Filter papers 115 3.35 Crucibles with permanent porous plates 117 3.36 Washing precipitates 11 8 3.37 Drying and igniting precipitates 119 3.38 References for Part A 122 3.39 Selected bibliography for Part A 122 PART B ERRORS, STATISTICS, AND SAMPLING CHAPTER 4 ERRORS AND STATISTICS 4.1 Limitations of analytical methods 127 4.2 Classification of errors 127 4.3 Accuracy 128 4.4 Precision 129 4.5 Minimisation of errors 131 4.6 Significant figures and computations 132 4.7 The use of calculators and microcomputers 133 4.8 Mean and standard deviation 134 4.9 Distribution of random errors 136 4.10 Reliability of results 137 4.1 1 Confidence interval 138 4.12 Comparison of results 139 4.13 Comparison of the means of two samples 140 4.14 Paired t-test 142 4.15 The number of replicate determinations 142 4.16 Correlation and regression 144 4.17 Linear regression 145 4.18 Comparison of more than two means (analysis of variance) 146 4.19 The value of statistics 149 vii CONTENTS CHAPTER 5 SAMPLING 150 5.1 The basis of sampling 150 5.2 Sampling procedure 150 5.3 Sampling statistics 151 5.4 Sampling and physical state 153 5.5 Crushing and grinding 155 5.6 Hazards in sampling 155 5.7 References for Part B 156 5.8 Selected bibliography for Part B 156 PART C SEPARATIVE TECHNIQUES CHAPTER 6 SOLVENT EXTRACTION 6.1 General discussion 161 6.2 Factors favouring solvent extraction 163 6.3 Quantitative treatment of solvent extraction equilibria 165 6.4 Synergistic extraction 167 6.5 Ion-association complexes 168 6.6 Extraction reagents 169 6.7 Some practical considerations 172 SOME APPLICATIONS 175 6.8 Determination of beryllium as the acetylacetone complex 175 6.9 Determination of boron using ferroin 175 6.10 Determination of copper as the diethyldithiocarbamate complex 177 6.11 Determination of copper as the 'neo-cuproin' complex 178 6.12 Determination of iron as the 8-hydroxyquinolate 178 6.13 Determination of lead by the dithizone method 179 6.14 Determination of molybdenum by the thiocyanate method 180 6.15 Determination of nickel as the dimethylglyoxime complex 181 6.16 Determination of silver by extraction as its ion-association complex with 1,lO-phenanthroline and bromopyrogallol red 182 6.17 Determination of nickel by synergistic extraction 183 6.18 Extraction and determination of lead, cadmium, and copper using ammonium pyrollidine dithiocarbamate 184 CHAPTER 7 ION EXCHANGE 7.1 General discussion 186 7.2 Action of ion exchange resins 189 7.3 Ion exchange chromatography 194 7.4 Ion chromatography 197 7.5 Ion exchange in organic and aqueous-organic solvents 201 7.6 Chelating ion exchange resins 202 CONTENTS 7.7 Liquid ion exchangers 204 APPLICATIONS IN ANALYTICAL CHEMISTRY 205 7.8 Experimental techniques 205 7.9 Determination of the capacity of an ion exchange resin (column method) 207 7.10 Separation of zinc and magnesium on an anion exchanger 208 7.11 Separation of chloride and bromide on an anion exchanger 209 7.12 Determination of the total cation concentration in water 210 7.13 Separation of cadmium and zinc on an anion exchanger 210 7.14 Concentration of copper(I1) ions from a brine solution using a chelating ion exchange resin 212 7.15 Determination of anions using ion chromatography 213 CHAPTER 8 COLUMN AND THIN-LAYER LlQUlD CHROMATOGRAPHY 8.1 Introduction 216 8.2 Types of liquid chromatography 216 8.3 Equipment for HPLC 220 8.4 Derivatisation 228 8.5 Quantitative analysis 229 8.6 Thin-layer chromatography 229 8.7 High performance thin-layer chromatography (HPTLC) 232 8.8 Determination of aspirin, phenacetin and caffeine in a mixture 233 8.9 Thin-layer chromatography - The recovery of separated substances by elution techniques 233 CHAPTER 9 CAS CHROMATOGRAPHY 9.1 Introduction 235 9.2 Apparatus 235 9.3 Programmed-temperature gas chromatography 244 9.4 Quantitative analysis by GLC 245 9.5 Elemental analysis using gas chromatography 247 9.6 Determination of aluminium by gas chromatographic analysis of its tris(acety1acetonato) complex 248 9.7 Analysis of a mixture using the interna1 normalisation method 249 9.8 Determination of sucrose as its trimethylsilyl derivative using gas-liquid chromatography 250 9.9 References for Part C 251 9.10 Selected bibliography for Part C 253 CONTENTS PART D TITRIMETRY AND GRAVIMETRY 255 CHAPTER 10 TlTRlMETRlC ANALYSIS 10.1 Titrimetric analysis 257 10.2 Classification of reactions in titrimetric analysis 258 10.3 Standard solutions 259 10.4 Equivalents, normalities and oxidation numbers 260 10.5 Preparation of standard solutions 260 10.6 Primary and secondary standards 260 NEUTRALISATION TlTRATlONS 10.7 Neutralisation indicators 262 10.8 Preparation of indicator solutions 266 10.9 Mixed indicators 267 10.10 Universal or multiple range indicators 268 10.1 1 Neutralisation curves 269 10.12 Neutralisation of a strong acid with a strong base 269 10.13 Neutralisation of a weak acid with a strong base 272 10.14 Neutralisation of a weak base with a strong acid 274 10.15 Neutralisation of a weak acid with a weak base 275 10.16 Neutralisation of a polyprotic acid with a strong base 276 10.17 Titration of anions of weak acids with strong acids: 'displacement titrations' 277 10.18 Choice of indicators in neutralisation reactions 280 10.19 Titrations in non-aqueous solvents 281 10.20 Solvents for non-aqueous titrations 283 10.21 Indicators for non-aqueous titrations 283 10.22 Preparation of a standard acid 284 10.23 Preparation of constant boiling point hydrochloric acid 285 10.24 Direct preparation of 0.1M hydrochloric acid from the constant boiling point acid 285 10.25 Preparation of approximately 0.1M hydrochloric acid and standardisation 286 10.26 Preparation of standard alkali 289 10.27 Standardisation of approximately 0.1M sodium hydroxide 292 10.28 Other standard substances for acidimetry and alkalimetry 293 10.29 Standard barium hydroxide solution 294 10.30 Determination of the Na2C0, content of washing soda 295 10.31 Determination of the strength of concentrated acids 296 10.32 Determination of a mixture of carbonate and hydroxide (analysis of commercial caustic soda) 297 10.33 Determination of a mixture of carbonate and hydrogencarbonate 299 10.34 Determination of boric acid 299 10.35 Determination of ammonia in an ammonium salt 300 10.36 Determination of organic nitrogen (the Kjeldahl procedure) 302 10.37 Determination of nitrates 303 CONTENTS 10.38 Determination of phosphate (precipitation as quinoline molybdophosphate) 304 10.39 Determination of the relative molecular mass of an organic acid 305 10.40 Determination of hydroxyl groups in carbohydrates 306 10.41 Determination of a mixture of aniline and ethanolamine using a non-aqueous titration 307 10.42 Determination of the saponification value of oils and fats 308 COMPLEXATION TlTRATlONS 10.43 Introduction 309 10.44 A simple complexation titration 309 10.45 Titration curves 310 10.46 Types of EDTA titrations 311 10.47 Titration of mixtures, selectivity, masking and demasking agents 312 10.48 Meta1 ion indicators 314 10.49 Standard EDTA solutions 321 10.50 Some practical considerations 322 DETERMINATION OF INDIVIDUAL CATIONS 10.51 Determination of aluminium: back-titration 324 10.52 Determination of barium: direct titration 324 10.53 Determination of bismuth: direct titration 324 10.54 Determination of calcium: substitution titration 325 10.55 Determination of copper: direct titration 326 10.56 Determination of iron(II1): direct titration 326 10.57 Determination of nickel: direct titrations 327 10.58 Determination of silver: indirect method 327 10.59 Details for the determination of a selection of metal ions by EDTA titration 328 ANALYSIS OF MIXTURES OF CATIONS 10.60 Determination of calcium and magnesium 328 10.61 Determination of calcium in the presence of magnesium using EGTA as titrant 331 10.62 Determination of the total hardness (permanent and temporary) of water 332 10.63 Determination of calcium in the presence of barium using CDTA as titrant 333 10.64 Determination of calcium and lead in a mixture 333 10.65 Determination of magnesium, manganese and zinc in a mixture: use of fluoride ion as a demasking agent 334 10.66 Determination of chromium(II1) and iron(II1) in a mixture: an example of kinetic masking 335 10.67 Determination of manganese in presence of iron: analysis of ferro-manganese 336 10.68 Determination of nickel in presence of iron: analysis of nickel steel 336