2NaH2PO4 + 2e− → Na2HPO4 + HPO42− + H2↑
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- Reduction of sodium dihydrogenphosphate
- 2NaH2PO4Sodium dihydrogenphosphate + 2e−ElectronNa2HPO4Sodium hydrogenphosphate + HPO42−Hydrogenphosphate ion + ↑⟶
Reduction of sodium dihydrogenphosphate yields sodium hydrogenphosphate, hydrogenphosphate ion, and (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 sodium dihydrogenphosphate
- 2NaH2PO4Sodium dihydrogenphosphate + 2e−ElectronNa2HPO4Sodium hydrogenphosphate + HPO42−Hydrogenphosphate ion + ↑⟶
General equation
- Reduction of reducible species
- ReactantOxidizing agent + e− ⟶ ProductReduction product
Oxidation state of each atom
- Reduction of sodium dihydrogenphosphate
Reactants
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| NaH2PO4 | Sodium dihydrogenphosphate | 2 | Oxidizing | – |
| e− | Electron | 2 | – | Electron |
Products
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| Na2HPO4 | Sodium hydrogenphosphate | 1 | – | – |
| HPO42− | Hydrogenphosphate ion | 1 | – | – |
| 1 | Reduced | – |
Thermodynamic changes
Changes in standard condition (1)
- Reduction of sodium dihydrogenphosphate◆
ΔrG 82.21 kJ/mol K 0.40 × 10−14 pK 14.40
| 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 | 8.30 | 82.21 | −117.1 | – |
per 1 mol of | 4.15 | 41.10 | −58.55 | – |
per 1 mol of Electron | 4.15 | 41.10 | −58.55 | – |
per 1 mol of | 8.30 | 82.21 | −117.1 | – |
per 1 mol of Hydrogenphosphate ion | 8.30 | 82.21 | −117.1 | – |
| 8.30 | 82.21 | −117.1 | – |
Changes in standard condition (2)
- Reduction of sodium dihydrogenphosphate◆
ΔrG 99.8 kJ/mol K 0.33 × 10−17 pK 17.48
| 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 | 4.1 | 99.8 | 329 | – |
per 1 mol of | 2.0 | 49.9 | 165 | – |
per 1 mol of Electron | 2.0 | 49.9 | 165 | – |
per 1 mol of | 4.1 | 99.8 | 329 | – |
per 1 mol of Hydrogenphosphate ion | 4.1 | 99.8 | 329 | – |
| 4.1 | 99.8 | 329 | – |
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 |
|---|---|---|---|---|
| NaH2PO4 (cr) | -1536.8[1] | -1386.1[1] | 127.49[1] | 116.86[1] |
| NaH2PO4 (ai) | -1536.41[1] | -1392.17[1] | 149.4[1] | – |
| NaH2PO4 (cr) 1 hydrate | -1833.0[1] | – | – | – |
| NaH2PO4 (cr) 2 hydrate | -2128.4[1] | – | – | – |
| e− | – | – | – | – |
* (cr):Crystalline solid, (ai):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 |
|---|---|---|---|---|
| Na2HPO4 (cr) | -1748.1[1] | -1608.2[1] | 150.50[1] | 135.31[1] |
| Na2HPO4 (ai) | -1772.38[1] | -1612.98[1] | 84.5[1] | – |
| Na2HPO4 (cr) 2 hydrate | -2346.0[1] | -2088.5[1] | 221.3[1] | – |
| Na2HPO4 (cr) 7 hydrate | -3821.7[1] | -3279.8[1] | 434.59[1] | – |
| Na2HPO4 (cr) 12 hydrate | -5297.8[1] | -4467.8[1] | 633.83[1] | – |
| HPO42− (ao) | -1292.14[1] | -1089.15[1] | -33.5[1] | – |
| (g) | 0[1] | 0[1] | 130.684[1] | 28.824[1] |
| (ao) | -4.2[1] | 17.6[1] | 577[1] | – |
* (cr):Crystalline solid, (ai):Ionized aqueous solution, (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°, -1536.8 kJ · mol−1
- ^ ΔfG°, -1386.1 kJ · mol−1
- ^ S°, 127.49 J · K−1 · mol−1
- ^ Cp°, 116.86 J · K−1 · mol−1
- ^ ΔfH°, -1536.41 kJ · mol−1
- ^ ΔfG°, -1392.17 kJ · mol−1
- ^ S°, 149.4 J · K−1 · mol−1
- ^ ΔfH°, -1833.0 kJ · mol−1
- ^ ΔfH°, -2128.4 kJ · mol−1
- ^ ΔfH°, -1748.1 kJ · mol−1
- ^ ΔfG°, -1608.2 kJ · mol−1
- ^ S°, 150.50 J · K−1 · mol−1
- ^ Cp°, 135.31 J · K−1 · mol−1
- ^ ΔfH°, -1772.38 kJ · mol−1
- ^ ΔfG°, -1612.98 kJ · mol−1
- ^ S°, 84.5 J · K−1 · mol−1
- ^ ΔfH°, -2346.0 kJ · mol−1
- ^ ΔfG°, -2088.5 kJ · mol−1
- ^ S°, 221.3 J · K−1 · mol−1
- ^ ΔfH°, -3821.7 kJ · mol−1
- ^ ΔfG°, -3279.8 kJ · mol−1
- ^ S°, 434.59 J · K−1 · mol−1
- ^ ΔfH°, -5297.8 kJ · mol−1
- ^ ΔfG°, -4467.8 kJ · mol−1
- ^ S°, 633.83 J · K−1 · mol−1
- ^ ΔfH°, -1292.14 kJ · mol−1
- ^ ΔfG°, -1089.15 kJ · mol−1
- ^ S°, -33.5 J · K−1 · mol−1
- ^ ΔfH°, 0 kJ · mol−1
- ^ ΔfG°, 0 kJ · mol−1
- ^ S°, 130.684 J · K−1 · mol−1
- ^ Cp°, 28.824 J · K−1 · mol−1
- ^ ΔfH°, -4.2 kJ · mol−1
- ^ ΔfG°, 17.6 kJ · mol−1
- ^ S°, 577 J · K−1 · mol−1