Acid-base indicators (pH indicators) are substances (dyes) that change their color with a change in pH. There is no book available in the market directly on acid-base indicators, even though the use of acid-base indicators is widespread, growing rapidly, and has exploded recently. This updated handbook serves as a systematic and up-to-date library of information on 250+ acid-base indicators and as a practical guide for both chemists and non-chemists in industry and academia. Entries in this book are listed alphabetically and include eneral chmical name, chemical structure, other names, CA index name, CAS registry number, color index number, colour index name, Merck index number (The Merck Index, 15th Edition, 2013), chemical/dye class, molecular formula, molecular weight, physical form, solubility, melting point, boiling point, boiling point (calcd.), pH range, color-change at pH, pKa, pKa (calcd.), absorption (?max), emission (?max), molar extinction coefficient, quantum yield, synthesis, biological/medical applications, industrial applications, safety/toxicity, certification/approval and referencesNumerous recent references as well as original references (when reported) have been provided on various synthetic methods, biological/medical applications, industrial applications, and safety/toxicity data. This is the first ever book which provides safety/toxicity data with reference to acute toxicity, algal toxicity, amyloid toxicity, aquatic toxicity, bacterial toxicity, carcinogenicity, cardiotoxicity, cardiovascular toxicity, chromosomal aberrations, chronic toxicity, clastogenicity, cytotoxicity, developmental toxicity, DNA damage, ecotoxicity, embryotoxicity, endocrine disrupters, environmental toxicity, fish toxicity, genotoxicity, hematotoxicity, hepatocarcinogenicity, hepatotoxicity, immunotoxicity, membrane toxicity, microbial toxicity, mitochondrial toxicity, mutagenicity, nephrotoxicity, neurotoxicity, nucleic acid damage, ophthalmic toxicity, oral toxicity, ototoxicity, ovarian toxicity, photodynamic toxicity, photogenotoxicity, phototoxicity, phytotoxicity, pulmonary toxicity, reproductive toxicity, skin toxicity, subchronic toxicity, teratogenicity, tumorigenicity, vascular toxicity, and so on. The second edition of Handbook of Acid-Base Indicators (pH Indicators) has been revised, enlarged and updated with several recent references and added 53 new acid-base indicators. Further, the First Edition provides major applications of acid-base indicators, whereas the Second Edition provides biological/medical applications and industrial applications separately. The Second Edition also provides Certification by Biological Stain Commission (BSC) and Approval by Food & Drugs Administration (FDA) of acid-base indicators, wherever applicable. In addition, several appendixes have been provided at the end of the book for scientists to conveniently and easily find an acid-base indicator as per their need. These appendixes include CAS Registry Numbers, Colour Index Names and Colour Index Numbers, Acridines, Anthraquinones, Aromatics, Azo, Benzeins, Coumarins, Fluorescent, Hydrazines, Maleins, Miscellaneous, Naphthalenes, Nitro, Phenolnaphthaleins, Phthaleins, Quinolines, Sulfonephthaleins, Triphenylmethanes, and Xanthenes.