In acid-base titration, a sudden change in the color of the acid-base indicator is generally used to indicate the end point of the titration. The acid-base indicator is mostly an organic weak acid or an organic weak base. In an alkaline solution, the indicator loses protons from acid to basic (indicated by In-), and in acidic solutions, protons are converted from basic to acid (represented by HIn) with structure and color. Variety. Since the dissociation equilibrium constants KHlπ of the various indicators are different, the range of discoloration of various indicators is also different. Some are discolored in acidic solutions, some are near neutral, and some are discolored in alkaline solutions. Therefore, an appropriate acid-base indicator can be selected according to the pH value and the jump size of the acid-base titration point. For example, strong alkali titrates weak acid, and the solution is weakly alkaline when it is at the same time. When the pH jump near the point is also in the alkaline range, it is suitable to use phenolphthalein or thymol blue as an indicator, and discoloration in an acidic solution. The methyl orange is not acceptable; if the strong acid titrates the weak base, the solution is slightly acidic when the point is equal, and the pH jump near the equivalence point is also in the acidic range. At this time, methyl red, methyl orange and bromine are used. A cresol green indicator is suitable.
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Amino compound
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Oxy-containing amino compound
Cycloalkylamines, aromatic monoamines, aromatic polyamines and derivatives and salts thereof
Acyclic monoamines, polyamines and their derivatives and salts
Amide compound
Sulfonic acid amino compound
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Alcohols, phenols, phenolic compounds and derivatives
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2-cycloalcohol
Halogenated, sulfonated, nitrated or nitrosated derivatives of alcohols
Extremely halogenated, sulfonated, nitrated or nitrosated derivatives of phenols
Phenol and its halogenated, sulfonated, nitrated or nitrosated derivatives
Acyclic alcohol
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Nitrogen-containing compound
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Nitrile compound
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Organic derivative of hydrazine or hydrazine
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Terpenoid
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Ether compounds and their derivatives
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Ether, ether alcohol
Halogenation, sulfonation, nitration or nitrosation of ethers, ether alcohols, ether phenols
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Aldehyde
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Carboxylic compounds and derivatives
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Cyclic carboxylic acid
Halogenation, sulfonation, nitration or nitrosation of carboxylic acids
Halogenation, sulfonation, nitration or nitration of carboxylic anhydrides
Carboxylic acid halide
Carboxylic esters and their derivatives
Salt of carboxylic acid ester and its derivatives
Acyclic carboxylic acid
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Hydrocarbon compounds and their derivatives
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Aromatic hydrocarbon
Cyclic hydrocarbon
Hydrocarbon sulfonate
Hydrocarbon halide
Hydrocarbon nitrite
Acyclic hydrocarbon
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Ketone compound
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Alkyl ureas and their derivatives and salts
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Inorganic acid ester
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Heterocyclic compound
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Diazo, azo or azo compound
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Organosilicon compound
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Organometallic compound
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Organic palladium
Organic germanium, cobalt, strontium, barium, gallium, germanium, germanium, germanium, germanium, etc.
Organic calcium
Zirconium
Organic potassium
Organic
Organic lithium
Organic
Organic aluminum
Organotin
Organic manganese
Organic sodium
Organic nickel
Organic titanium
Organic iron
Organic copper
Organotin
Organic zinc
Organic
Organic
Organic germanium, mercury, silver, platinum, etc.
Organic germanium, antimony, bismuth, tungsten, antimony, bismuth, lead, vanadium, molybdenum, chromium, antimony, etc.
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Organic sulfur compound
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Organic phosphine compound
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Organometallic salt
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Organic fluorine compound
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Fluorobenzoic acid series
Fluorobenzonitrile series
Fluorobenzaldehyde series
Fluorobenzyl alcohol series
Fluoroanisole series
Fluoroaniline series
Fluorophenylacetic acid series
Fluorophenol series
Fluorobenzoic acid series
Fluoronitrobenzene series
Fluoropyridine series
Potassium fluoroborate series
Fluorobenzyl alcohol series
Fluorotoluene series
Fluorine red series
Fluoroethane series
Fluoropropane series