3H2SeO4 + 2e− → SeO2 + 2H3O+ + 2SeO42−
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- Reduction of selenic acid
Reduction of selenic acid yields selenium dioxide, hydronium ion, and selenate 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 selenic acid
General equation
- Reduction of reducible species
- ReactantOxidizing agent + e− ⟶ ProductReduction product
Oxidation state of each atom
- Reduction of selenic acid
Reactants
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| H2SeO4 | Selenic acid | 3 | Oxidizing | – |
| e− | Electron | 2 | – | Electron |
Products
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| SeO2 | Selenium dioxide | 1 | Reduced | – |
| H3O+ | Hydronium ion | 2 | – | – |
| SeO42− | Selenate ion | 2 | – | – |
Thermodynamic changes
Changes in standard condition
- Reduction of selenic acid
| 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 | −401.2 | – | – | – |
per 1 mol of | −133.7 | – | – | – |
per 1 mol of Electron | −200.6 | – | – | – |
per 1 mol of | −401.2 | – | – | – |
per 1 mol of Hydronium ion | −200.6 | – | – | – |
per 1 mol of Selenate ion | −200.6 | – | – | – |
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 |
|---|---|---|---|---|
| H2SeO4 (cr) | -530.1[1] | – | – | – |
| H2SeO4 (cr) 1 hydrate | -840.6[1] | – | – | – |
| H2SeO4 (l) 1 hydrate | -820.5[1] | – | – | – |
| e− | – | – | – | – |
* (cr):Crystalline solid, (l):Liquid
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 |
|---|---|---|---|---|
| SeO2 (cr) | -225.35[1] | – | – | – |
| SeO2 (aq) | -221.63[1] | – | – | – |
| H3O+ (ao) | -285.830[1] | -237.129[1] | 69.91[1] | 75.291[1] |
| SeO42− (ao) | -599.1[1] | -441.3[1] | 54.0[1] | – |
* (cr):Crystalline solid, (aq):Aqueous solution, (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°, -530.1 kJ · mol−1
- ^ ΔfH°, -840.6 kJ · mol−1
- ^ ΔfH°, -820.5 kJ · mol−1
- ^ ΔfH°, -225.35 kJ · mol−1
- ^ ΔfH°, -221.63 kJ · 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°, -599.1 kJ · mol−1
- ^ ΔfG°, -441.3 kJ · mol−1
- ^ S°, 54.0 J · K−1 · mol−1