HPO42− + H2O → H2PO4− + OH−
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The reaction of hydrogenphosphate ion and water yields dihydrogenphosphate ion and hydroxide ion (Other reactions are here). This reaction is an acid-base reaction and is classified as follows:
Table of contents
Reaction data
Chemical equation
- Reaction of hydrogenphosphate ion and water
General equation
- Cation/AnionBrønsted base + H2OBrønsted acid ⟶ Proton donating ion/AcidConjugate acid + OH−Conjugate base
Oxidation state of each atom
- Reaction of hydrogenphosphate ion and water
Reactants
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| HPO42− | Hydrogenphosphate ion | 1 | Brønsted base | Anion |
| H2O | Water | 1 | Brønsted acid | Water |
Products
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| H2PO4− | Dihydrogenphosphate ion | 1 | Conjugate acid | Proton donating ion |
| OH− | Hydroxide ion | 1 | Conjugate base | Hydroxide ion |
Thermodynamic changes
Changes in standard condition
| Standard enthalpy of reaction ΔrH° kJ · mol−1 | Standard Gibbs energy of reaction ΔrG° kJ · mol−1 | Standard entropy of reaction ΔrS° J · K−1 · mol−1 | Standard heat capacity of reaction at constant pressure ΔrCp° J · K−1 · mol−1 | |
|---|---|---|---|---|
per 1 mol of Equation | 51.69 | 38.76 | 43.2 | – |
per 1 mol of Hydrogenphosphate ion | 51.69 | 38.76 | 43.2 | – |
per 1 mol of | 51.69 | 38.76 | 43.2 | – |
per 1 mol of Dihydrogenphosphate ion | 51.69 | 38.76 | 43.2 | – |
per 1 mol of Hydroxide ion | 51.69 | 38.76 | 43.2 | – |
Thermodynamic data of reactants
| Chemical formula | 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 |
|---|---|---|---|---|
| HPO42− (ao) | -1292.14[1] | -1089.15[1] | -33.5[1] | – |
| H2O (cr) | – | – | – | – |
| H2O (l) | -285.830[1] | -237.129[1] | 69.91[1] | 75.291[1] |
| H2O (g) | -241.818[1] | -228.572[1] | 188.825[1] | 33.577[1] |
* (ao):Un-ionized aqueous solution, (cr):Crystalline solid, (l):Liquid, (g):Gas
Thermodynamic data of products
| Chemical formula | 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 |
|---|---|---|---|---|
| H2PO4− (ao) | -1296.29[1] | -1130.28[1] | 90.4[1] | – |
| OH− (g) | -143.5[1] | – | – | – |
| OH− (ao) | -229.994[1] | -157.244[1] | -10.75[1] | -148.5[1] |
* (ao):Un-ionized aqueous solution, (g):Gas
References
List of references
- 1Janiel 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)
- ^ ΔfH°, -1292.14 kJ · mol−1
- ^ ΔfG°, -1089.15 kJ · mol−1
- ^ S°, -33.5 J · K−1 · mol−1
- ^ ΔfH°, -285.830 kJ · mol−1
- ^ ΔfG°, -237.129 kJ · mol−1
- ^ S°, 69.91 J · K−1 · mol−1
- ^ Cp°, 75.291 J · K−1 · mol−1
- ^ ΔfH°, -241.818 kJ · mol−1
- ^ ΔfG°, -228.572 kJ · mol−1
- ^ S°, 188.825 J · K−1 · mol−1
- ^ Cp°, 33.577 J · K−1 · mol−1
- ^ ΔfH°, -1296.29 kJ · mol−1
- ^ ΔfG°, -1130.28 kJ · mol−1
- ^ S°, 90.4 J · K−1 · mol−1
- ^ ΔfH°, -143.5 kJ · mol−1
- ^ ΔfH°, -229.994 kJ · mol−1
- ^ ΔfG°, -157.244 kJ · mol−1
- ^ S°, -10.75 J · K−1 · mol−1
- ^ Cp°, -148.5 J · K−1 · mol−1