Citric Acid

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Citric Acid (Wikipedia)
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Citric acid
Zitronensäure - Citric acid.svg
IUPAC name
3-carboxy-3-hydroxypentane-1,5-dioic acid
Other names
Citric Acid
3-carboxy-3-hydroxypentanedioic acid
2-hydroxy-1,2,3-propanetricarboxylic acid
77-92-9 YesY
ChemSpider305 YesY
DrugBankDB04272 YesY
EC Number201-069-1
Jmol 3D imageInteractive graph
KEGGD00037 YesY
PubChem22230 (monohydrate) 311, 22230 (monohydrate)
RTECS numberGE7350000
Molar mass192.12 g·mol−1
Appearancecrystalline white solid
Density1.665 g/cm3 (anhydrous)
1.542 g/cm3 (18 °C, monohydrate)
Melting point156 °C (313 °F; 429 K)
Boiling point310 °C (590 °F; 583 K) decomposes from 175 °C
117.43 g/100 mL (10 °C)
147.76 g/100 mL (20 °C)
180.89 g/100 mL (30 °C)
220.19 g/100 mL (40 °C)
382.48 g/100 mL (80 °C)
547.79 g/100 mL (100 °C)
Solubilitysoluble in alcohol, ether, ethyl acetate, DMSO
insoluble in C6H6, CHCl3, CS2, toluene
Solubility in ethanol62 g/100 g (25 °C)
Solubility in amyl acetate4.41 g/100 g (25 °C)
Solubility in diethyl ether1.05 g/100 g (25 °C)
Solubility in 1,4-Dioxane35.9 g/100 g (25 °C)
log P-1.64
Acidity (pKa)pKa1 = 3.13
pKa2 = 4.76
pKa3 = 6.39, 6.40
1.493 - 1.509 (20 °C)
1.46 (150 °C)
Viscosity6.5 cP (50% aq. sol.)
226.51 J/mol·K (26.85 °C)
252.1 J/mol·K
-1548.8 kJ/mol
-1960.6 kJ/mol
-1972.34 kJ/mol (monohydrate)
A09AB04 (WHO)
Main hazardsskin and eye irritant
Safety data sheetHMDB
GHS pictogramsThe exclamation-mark pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)
GHS signal wordWarning
Irritant Xi Corrosive C
R-phrasesR34, R36/37/38, R41
S-phrasesS24/25, S26, S36/37/39, S45
NFPA 704
Flash point155 °C (311 °F; 428 K)
345 °C (653 °F; 618 K)
Explosive limits8%
Lethal dose or concentration (LD, LC):
3000 mg/kg (rats, oral)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YesYN ?)
Infobox references

Citric acid is a weak organic tribasic acid. It occurs naturally in citrus fruits. In biochemistry, it is an intermediate in the citric acid cycle, which occurs in the metabolism of all aerobic organisms.

More than a million tons of citric acid are manufactured every year. It is used widely as an acidifier, as a flavoring, and as a chelating agent.

A citrate is a derivative of citric acid; that is, the salts, esters, and the polyatomic anion found in solution. An example of the former, a salt is trisodium citrate; an ester is triethyl citrate. When part of a salt, the formula of the citrate ion is written as C6H5O73− or C3H5O(COO)33−.

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