Monosodium phosphate
Phosphorus, P Oxygen, O Hydrogen, H Sodium, Na | |
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IUPAC name Sodium dihydrogen phosphate | |
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ECHA InfoCard | 100.028.591 |
E number | E339(i) (antioxidants, ...) |
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CompTox Dashboard (EPA) |
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InChI
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Properties | |
Chemical formula | NaH2PO4 |
Molar mass | 119.976 g·mol−1 |
Appearance | White powder or crystals |
Density | 2.36 g/cm3 (anhydrous) |
Solubility in water | 59.90 g/(100 mL) (0°C) |
Hazards | |
NFPA 704 (fire diamond) | 0 0 0 |
Flash point | Non-flammable |
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Related compounds | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references |
Monosodium phosphate (MSP), also known as monobasic sodium phosphate and sodium dihydrogen phosphate, is an inorganic compound with the chemical formula NaH2PO4. It is a sodium salt of phosphoric acid. It consists of sodium cations (Na+) and dihydrogen phosphate anions (H2PO−4). One of many sodium phosphates, it is a common industrial chemical. The salt exists in an anhydrous form, as well as monohydrate and dihydrate (NaH2PO4·H2O and NaH2PO4·2H2O respectively).[1]
Production and reactions
The salt is obtained by partial neutralization of phosphoric acid. The pKa of monosodium phosphate is 6.8-7.2 (depending on the physicochemical characteristics during pKa determination).[2]
Heating this salt above 169 °C gives disodium pyrophosphate:
- 2 NaH2PO4 → Na2H2P2O7 + H2O
When heated at 550 °C, anhydrous trisodium trimetaphosphate is formed:[3]
- 3 NaH2PO4 → Na3P3O9 + 3 H2O
Uses
Phosphates are often used in foods and in water treatment. The pH of such formulations is generally adjusted by mixtures of various sodium phosphates, such as this salt.[1] The sodium chloride equivalent value, or E-Value, is 0.49.[clarification needed] It is soluble in 4.5 parts water.[clarification needed]
Food additive
It is added in animal feed, toothpaste, and evaporated milk. It is used as a thickening agent and emulsifier.
Detection of magnesium
Monosodium phosphate is used to detect the presence of magnesium ions in salts. Formation of a white precipitate on the addition of ammonium chloride, ammonium hydroxide and monosodium phosphate to an aqueous or dilute HCl solution of the salt indicates presence of magnesium ions.
Notes
- ^ a b Schrödter, Klaus; Bettermann, Gerhard; Staffel, Thomas; Wahl, Friedrich; Klein, Thomas; Hofmann, Thomas (2008). "Phosphoric Acid and Phosphates". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a19_465.pub3. ISBN 978-3527306732.
- ^ Salaun, F.: "Influence of mineral environment on the buffering capacity of casein micelles" Archived 2012-03-13 at the Wayback Machine, "Milchwissenschaft", 62(1):3
- ^ Bell, R. N. (1950). "Sodium Metaphosphates". Inorganic Syntheses. Vol. 3. pp. 103–106. doi:10.1002/9780470132340.ch26. ISBN 9780470132340.
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Halides | |
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Chalcogenides | |
Pnictogenides |
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Oxyhalides | |
Oxychalcogenides |
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Oxypnictogenides |
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Others |
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- CH3ONa
- C2H5ONa
- HCOONa
- C2H5COONa
- C3H7COONa
- Na2C4H4O6
- C4H5NaO6
- NaCH3COO
- NaC6H5CO2
- NaC6H4(OH)CO2
- NaC12H23O2
- NaC10H8
- Na2[Fe[CN5]NO]
- C6H16AlNaO4
- NaC6H7O6
- C5H8NO4Na
- C6H5Na
- C4H9Na
- NaC5H5
- C15H31COONa
- C17H33COONa
- C18H35O2Na
- C164H256O68S2Na2