4K3[Fe(CN)6] + 4e− → 3K4[Fe(CN)6] + Fe2+ + 6CN−
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- Reduction of potassium hexacyanidoferrate(III)
- 4K3[Fe(CN)6]Potassium hexacyanidoferrate(III) + 4e−Electron3K4[Fe(CN)6]Potassium hexacyanidoferrate(II) + Fe2+Iron(II) ion + 6CN−Cyanide ion⟶
Reduction of potassium hexacyanidoferrate(III) yields potassium hexacyanidoferrate(II), iron(II) ion, and cyanide 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 potassium hexacyanidoferrate(III)
- 4K3[Fe(CN)6]Potassium hexacyanidoferrate(III) + 4e−Electron3K4[Fe(CN)6]Potassium hexacyanidoferrate(II) + Fe2+Iron(II) ion + 6CN−Cyanide ion⟶
General equation
- Reduction of reducible species
- ReactantOxidizing agent + e− ⟶ ProductReduction product
Oxidation state of each atom
- Reduction of potassium hexacyanidoferrate(III)
Reactants
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| K3[Fe(CN)6] | Potassium hexacyanidoferrate(III) | 4 | Oxidizing | – |
| e− | Electron | 4 | – | Electron |
Products
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| K4[Fe(CN)6] | Potassium hexacyanidoferrate(II) | 3 | Reduced | – |
| Fe2+ | Iron(II) ion | 1 | Reduced | – |
| CN− | Cyanide ion | 6 | – | – |
Thermodynamic changes
Changes in standard condition
- Reduction of potassium hexacyanidoferrate(III)◆
ΔrG 123.1 kJ/mol K 0.27 × 10−21 pK 21.57 - 4K3[Fe(CN)6]Ionized aqueous solution + 4e−3K4[Fe(CN)6]Ionized aqueous solution + Fe2+Un-ionized aqueous solution + 6CN−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 | −65.9 | 123.1 | −369.3 | – |
per 1 mol of | −16.5 | 30.77 | −92.33 | – |
per 1 mol of Electron | −16.5 | 30.77 | −92.33 | – |
per 1 mol of | −22.0 | 41.03 | −123.1 | – |
per 1 mol of Iron(II) ion | −65.9 | 123.1 | −369.3 | – |
per 1 mol of Cyanide ion | −11.0 | 20.52 | −61.55 | – |
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 |
|---|---|---|---|---|
| K3[Fe(CN)6] (cr) | -249.8[1] | -129.6[1] | 426.06[1] | – |
| K3[Fe(CN)6] (ai) | -195.4[1] | -120.4[1] | 577.8[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 |
|---|---|---|---|---|
| K4[Fe(CN)6] (cr) | -594.1[1] | -453.0[1] | 418.8[1] | 332.21[1] |
| K4[Fe(CN)6] (ai) | -554.0[1] | -438.01[1] | 505.0[1] | – |
| K4[Fe(CN)6] (cr) 3 hydrate | -1466.5[1] | -1168.8[1] | 593.7[1] | 482.42[1] |
| Fe2+ (g) | 2749.93[1] | – | – | – |
| Fe2+ (ao) | -89.1[1] | -78.90[1] | -137.7[1] | – |
| CN− (ao) | 150.6[1] | 172.4[1] | 94.1[1] | – |
* (cr):Crystalline solid, (ai):Ionized aqueous solution, (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°, -249.8 kJ · mol−1
- ^ ΔfG°, -129.6 kJ · mol−1
- ^ S°, 426.06 J · K−1 · mol−1
- ^ ΔfH°, -195.4 kJ · mol−1
- ^ ΔfG°, -120.4 kJ · mol−1
- ^ S°, 577.8 J · K−1 · mol−1
- ^ ΔfH°, -594.1 kJ · mol−1
- ^ ΔfG°, -453.0 kJ · mol−1
- ^ S°, 418.8 J · K−1 · mol−1
- ^ Cp°, 332.21 J · K−1 · mol−1
- ^ ΔfH°, -554.0 kJ · mol−1
- ^ ΔfG°, -438.01 kJ · mol−1
- ^ S°, 505.0 J · K−1 · mol−1
- ^ ΔfH°, -1466.5 kJ · mol−1
- ^ ΔfG°, -1168.8 kJ · mol−1
- ^ S°, 593.7 J · K−1 · mol−1
- ^ Cp°, 482.42 J · K−1 · mol−1
- ^ ΔfH°, 2749.93 kJ · mol−1
- ^ ΔfH°, -89.1 kJ · mol−1
- ^ ΔfG°, -78.90 kJ · mol−1
- ^ S°, -137.7 J · K−1 · mol−1
- ^ ΔfH°, 150.6 kJ · mol−1
- ^ ΔfG°, 172.4 kJ · mol−1
- ^ S°, 94.1 J · K−1 · mol−1