13H3PO4 + 8e− → PH3↑ + 12H2PO4− + 4H3O+
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- Reduction of phosphoric acid
Reduction of phosphoric acid yields , dihydrogenphosphate ion, and hydronium ion (Other reactions are here). This reaction is an oxidation-reduction reaction and is classified as follows:
Table of contents
Reaction data
Chemical equation
- Reduction of phosphoric acid
General equation
- Reduction of reducible species
- ReactantOxidizing agent + e− ⟶ ProductReduction product
Oxidation state of each atom
- Reduction of phosphoric acid
Reactants
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| H3PO4 | Phosphoric acid | 13 | Oxidizing | – |
| e− | Electron | 8 | – | Electron |
Products
Thermodynamic changes
Changes in standard condition (1)
- Reduction of phosphoric acid◆
ΔrG 354.5 kJ/mol K 0.78 × 10−62 pK 62.11 - 13H3PO4Un-ionized aqueous solution + 8e−↑Gas + 12H2PO4−Un-ionized aqueous solution + 4H3O+Un-ionized aqueous solution⟶
| 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 | 55.0 | 354.5 | −481.9 | – |
per 1 mol of | 4.23 | 27.27 | −37.07 | – |
per 1 mol of Electron | 6.88 | 44.31 | −60.24 | – |
| 55.0 | 354.5 | −481.9 | – | |
per 1 mol of Dihydrogenphosphate ion | 4.58 | 29.54 | −40.16 | – |
per 1 mol of Hydronium ion | 13.8 | 88.63 | −120.5 | – |
Changes in standard condition (2)
- Reduction of phosphoric acid◆
ΔrG 366.50 kJ/mol K 0.62 × 10−64 pK 64.21 - 13H3PO4Un-ionized aqueous solution + 8e−↑Un-ionized aqueous solution + 12H2PO4−Un-ionized aqueous solution + 4H3O+Un-ionized aqueous solution⟶
| 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 | 40.12 | 366.50 | −572.1 | – |
per 1 mol of | 3.086 | 28.192 | −44.01 | – |
per 1 mol of Electron | 5.015 | 45.813 | −71.51 | – |
| 40.12 | 366.50 | −572.1 | – | |
per 1 mol of Dihydrogenphosphate ion | 3.343 | 30.542 | −47.68 | – |
per 1 mol of Hydronium ion | 10.03 | 91.625 | −143.0 | – |
Changes in standard condition (3)
- Reduction of phosphoric acid◆
ΔrG −1255.4 kJ/mol K 8.64 × 10219 pK −219.94 - 13H3PO4Ionized aqueous solution + 8e−↑Gas + 12H2PO4−Un-ionized aqueous solution + 4H3O+Un-ionized aqueous solution⟶
| 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 | −87.2 | −1255.4 | 4438.6 | – |
per 1 mol of | −6.71 | −96.569 | 341.43 | – |
per 1 mol of Electron | −10.9 | −156.93 | 554.83 | – |
| −87.2 | −1255.4 | 4438.6 | – | |
per 1 mol of Dihydrogenphosphate ion | −7.27 | −104.62 | 369.88 | – |
per 1 mol of Hydronium ion | −21.8 | −313.85 | 1109.7 | – |
Changes in standard condition (4)
- Reduction of phosphoric acid◆
ΔrG −1243.4 kJ/mol K 6.83 × 10217 pK −217.83 - 13H3PO4Ionized aqueous solution + 8e−↑Un-ionized aqueous solution + 12H2PO4−Un-ionized aqueous solution + 4H3O+Un-ionized aqueous solution⟶
| 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 | −102.1 | −1243.4 | 4348.4 | – |
per 1 mol of | −7.854 | −95.646 | 334.49 | – |
per 1 mol of Electron | −12.76 | −155.43 | 543.55 | – |
| −102.1 | −1243.4 | 4348.4 | – | |
per 1 mol of Dihydrogenphosphate ion | −8.508 | −103.62 | 362.37 | – |
per 1 mol of Hydronium ion | −25.52 | −310.85 | 1087.1 | – |
Changes in standard condition (5)
- Reduction of phosphoric acid◆
ΔrG 354.5 kJ/mol K 0.78 × 10−62 pK 62.11 - 13H3PO4Un-ionized aqueous solution + 8e−↑Gas + 12H2PO4−Un-ionized aqueous solution + 4H3O+Un-ionized aqueous solution⟶
| 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 | 55.0 | 354.5 | −481.9 | – |
per 1 mol of | 4.23 | 27.27 | −37.07 | – |
per 1 mol of Electron | 6.88 | 44.31 | −60.24 | – |
| 55.0 | 354.5 | −481.9 | – | |
per 1 mol of Dihydrogenphosphate ion | 4.58 | 29.54 | −40.16 | – |
per 1 mol of Hydronium ion | 13.8 | 88.63 | −120.5 | – |
Changes in standard condition (6)
- Reduction of phosphoric acid◆
ΔrG 366.50 kJ/mol K 0.62 × 10−64 pK 64.21 - 13H3PO4Un-ionized aqueous solution + 8e−↑Un-ionized aqueous solution + 12H2PO4−Un-ionized aqueous solution + 4H3O+Un-ionized aqueous solution⟶
| 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 | 40.12 | 366.50 | −572.1 | – |
per 1 mol of | 3.086 | 28.192 | −44.01 | – |
per 1 mol of Electron | 5.015 | 45.813 | −71.51 | – |
| 40.12 | 366.50 | −572.1 | – | |
per 1 mol of Dihydrogenphosphate ion | 3.343 | 30.542 | −47.68 | – |
per 1 mol of Hydronium ion | 10.03 | 91.625 | −143.0 | – |
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 |
|---|---|---|---|---|
| H3PO4 (cr) | -1279.0[1] | -1119.1[1] | 110.50[1] | 106.06[1] |
| H3PO4 (l) | -1266.9[1] | – | – | – |
| H3PO4 (ai) | -1277.4[1] | -1018.7[1] | -220.3[1] | – |
| H3PO4 (ao) | -1288.34[1] | -1142.54[1] | 158.2[1] | – |
| H3PO4 (cr) 0.5 hydrate | -1431.3[1] | -1242.1[1] | 129.16[1] | 126.02[1] |
| H3PO4 (cr) 1 hydrate | -1568.83[1] | – | – | – |
| e− | – | – | – | – |
* (cr):Crystalline solid, (l):Liquid, (ai):Ionized aqueous solution, (ao):Un-ionized aqueous solution
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 |
|---|---|---|---|---|
| (g) | 5.4[1] | 13.4[1] | 210.23[1] | 37.11[1] |
| (ao) | -9.50[1] | 25.36[1] | 120.1[1] | – |
| H2PO4− (ao) | -1296.29[1] | -1130.28[1] | 90.4[1] | – |
| H3O+ (ao) | -285.830[1] | -237.129[1] | 69.91[1] | 75.291[1] |
* (g):Gas, (ao):Un-ionized aqueous solution
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°, -1279.0 kJ · mol−1
- ^ ΔfG°, -1119.1 kJ · mol−1
- ^ S°, 110.50 J · K−1 · mol−1
- ^ Cp°, 106.06 J · K−1 · mol−1
- ^ ΔfH°, -1266.9 kJ · mol−1
- ^ ΔfH°, -1277.4 kJ · mol−1
- ^ ΔfG°, -1018.7 kJ · mol−1
- ^ S°, -220.3 J · K−1 · mol−1
- ^ ΔfH°, -1288.34 kJ · mol−1
- ^ ΔfG°, -1142.54 kJ · mol−1
- ^ S°, 158.2 J · K−1 · mol−1
- ^ ΔfH°, -1431.3 kJ · mol−1
- ^ ΔfG°, -1242.1 kJ · mol−1
- ^ S°, 129.16 J · K−1 · mol−1
- ^ Cp°, 126.02 J · K−1 · mol−1
- ^ ΔfH°, -1568.83 kJ · mol−1
- ^ ΔfH°, 5.4 kJ · mol−1
- ^ ΔfG°, 13.4 kJ · mol−1
- ^ S°, 210.23 J · K−1 · mol−1
- ^ Cp°, 37.11 J · K−1 · mol−1
- ^ ΔfH°, -9.50 kJ · mol−1
- ^ ΔfG°, 25.36 kJ · mol−1
- ^ S°, 120.1 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°, -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