Sodium dihydrogenphosphate
Sodium dihydrogenphosphate is an inorganic compound with formula NaH2PO4.
- 1Names
- 2Formulae and structures
- 3Properties
- 4Constituents
- 5Thermodynamic properties
- 6Solubility
- 7Preparations
- 8Chemical reactions
- 9References
- 10Related substances
- 11Related categories
Names
List of substance names
- Typical name
- Sodium dihydrogenphosphate
- Compositional nomenclature
- Sodium dihydrogenphosphate
- Monosodium dihydrogenphosphate
- Additive nomenclature
- Sodium dihydroxidodioxidophosphate(1−)
- Hydrogen nomenclature
- Sodium dihydrogen(tetraoxidophosphate)(1−)
- Other names
- Sodium dihydrogen phosphate
- Monosodium dihydrogen phosphate
Formulae and structures
List of formulae
- Typical formula
- NaH2PO4
- Compositional formula
- NaH2PO4
- Structural formula
- Other structural formulas
- Lewis structure
- Colored Lewis structure
Properties
List of substance properties
Constituents
Constituent ions
| Ion | Name | Charge number | Number |
|---|---|---|---|
| Na+ | Sodium ion | 1 | 1 |
| H2PO4− | Dihydrogenphosphate ion | -1 | 1 |
Constituent atoms
| Atom | Name | Oxidation state | Number |
|---|---|---|---|
| Na | Sodium | +1 | 1 |
| H | Hydrogen | +1 | 2 |
| P | Phosphorus | +5 | 1 |
| O | Oxygen | −2 | 4 |
Ratio of atoms
| Atom | Atomic weight | Number | Atomic ratio | Weight ratio |
|---|---|---|---|---|
| Na | 22.990 | 1 | 12.50% | 19.16% |
| H | 1.008 | 2 | 25.00% | 1.68% |
| P | 30.974 | 1 | 12.50% | 25.82% |
| O | 15.999 | 4 | 50.00% | 53.34% |
Thermodynamic properties
Phase transition properties
- Enthalpy of fusion
- –
- Enthalpy of vaporization
- –
- Enthalpy of vaporization at 25°C
- –
- Enthalpy of other transition
- –
Standard thermodynamic properties
State | Standard enthalpy of formation ΔfH° kJ · mol−1 | Standard Gibbs energy of formation ΔfG° kJ · mol−1 | Standard molar entropy S° J · K−1 · mol−1 | Standard molar heat capacity at constant pressure Cp° J · K−1 · mol−1 |
|---|---|---|---|---|
| Crystalline solid | −1536.8[3] | −1386.1[3] | 127.49[3] | 116.86[3] |
| Ionized aqueous solution | −1536.41[3] | −1392.17[3] | 149.4[3] | – |
| Crystalline solid 1 hydrate | −1833.0[3] | – | – | – |
| Crystalline solid 2 hydrate | −2128.4[3] | – | – | – |
Solubility
Qualitative solubility
Solubility in water (g/100 g)[1]
| 0°C | 10°C | 20°C | 30°C | 40°C | 60°C | 80°C | 90°C |
|---|---|---|---|---|---|---|---|
| 56.5 | 69.8 | 86.9 | 107 | 133 | 172 | 211 | 234 |
Solubility in water (g/100 g)[4]
| 0.1°C | 5°C | 10°C | 15°C | 20°C | 25°C | 30°C | 35°C | 40°C | 41°C | 45°C | 50°C | 55°C | 57°C | 60°C | 65°C | 69°C | 80°C | 90°C | 99.1°C |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 57.86 | 63.82 | 69.87 | 76.72 | 85.21 | 94.63 | 106.45 | 120.44 | 138.16 | 142.55 | 148.2 | 158.61 | 170.85 | 175.81 | 179.33 | 184.99 | 190.24 | 207.29 | 225.31 | 246.56 |
Solubility curve (g/100 g)
Preparations
Reaction of acid and base
The reaction of phosphoric acid and sodium hydroxide yields sodium dihydrogenphosphate and water.
Reaction of base, acidic oxide, and water
The reaction of sodium hydroxide, tetraphosphorus decaoxide, and water yields sodium dihydrogenphosphate.
Reaction of basic oxide and acid
The reaction of sodium oxide and phosphoric acid yields sodium dihydrogenphosphate and water.
Reaction of salt of weak base and strong base
The reaction of ammonium phosphate and sodium hydroxide yields sodium dihydrogenphosphate, ammonia, and water.
Reaction of salt and acid
The reaction of salt and acid can yield sodium dihydrogenphosphate.
Reaction of salt, acidic oxide, and water
The reaction of salt, acidic oxide, and water can yield sodium dihydrogenphosphate.
Reaction of active metal and acid
The reaction of and phosphoric acid yields sodium dihydrogenphosphate and .
Chemical reactions
Electrolytic dissociation
Electrolytic dissociation of sodium dihydrogenphosphate yields sodium ion and anion.
Reaction with strong acid
The reaction of sodium dihydrogenphosphate and strong acid yields salt of strong acid and phosphoric acid.
Reaction with base
The reaction of sodium dihydrogenphosphate and base yields salt and water.
Reaction with reducing species
The reaction of reducing species and sodium dihydrogenphosphate yields a variety of products.
Reaction with oxidizable species
The reaction of oxidizable species and sodium dihydrogenphosphate yields a variety of products.
Reaction with oxidizing species
The reaction of sodium dihydrogenphosphate and oxidizing species yields a variety of products.
Precipitation reaction
When a certain chemical species is present in aqueous solution, it reacts with sodium dihydrogenphosphate to form a precipitate.
Decomposition
Decomposition of sodium dihydrogenphosphate yields a variety of products.
Electrolysis of aqueous solution
Electrolysis of aqueous sodium dihydrogenphosphate yields a variety of products.
References
List of references
- 1James G. Speight (2017)Lange's Handbook of Chemistry, 17th editionMcGraw Hill Education
- 2John R. Rumble Jr, David R. Lide, Thomas J. Bruno (2019)CRC Handbook of Chemistry and Physics 100th EditionCRC Press
- ^ Melting point, 200 °C - p.4-49
- 3Janiel J. Reed (1989)The NBS Tables of Chemical Thermodynamic Properties: Selected Values for Inorganic and C1 and C2 Organic Substances in SI UnitsNational Institute of Standards and Technology (NIST)
- 4Atherton Seidell (1919)Solubilities of Inorganic and Organic Compounds: A Compilation of Quantitative Solubility Data From the Periodical LiteratureD. Van Nostrand Company
