K4[Fe(CN)6] + 6HI → 4KI + FeI2 + 6HCN
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The reaction of potassium hexacyanidoferrate(II) and hydrogen iodide yields potassium iodide, iron(II) iodide, and hydrogen cyanide. This reaction is an acid-base reaction and is classified as follows:
Table of contents
Reaction data
Chemical equation
- Reaction of potassium hexacyanidoferrate(II) and hydrogen iodide
General equation
- Salt of weak acidBrønsted base + Strong acidBrønsted acid ⟶ Salt of strong acidConjugate base + Weak acidConjugate acid
Oxidation state of each atom
- Reaction of potassium hexacyanidoferrate(II) and hydrogen iodide
Reactants
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| K4[Fe(CN)6] | Potassium hexacyanidoferrate(II) | 1 | Brønsted base | Salt of weak acid |
| HI | Hydrogen iodide | 6 | Brønsted acid | Strong acid |
Products
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| KI | Potassium iodide | 4 | Conjugate base | Salt of strong acid |
| FeI2 | Iron(II) iodide | 1 | Conjugate base | Salt of strong acid |
| HCN | Hydrogen cyanide | 6 | Conjugate acid | Weak acid |
Thermodynamic changes
Changes in standard condition
- Reaction of potassium hexacyanidoferrate(II) and hydrogen iodide
| 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 | −336.2 | – | – | – |
per 1 mol of | −336.2 | – | – | – |
per 1 mol of | −56.03 | – | – | – |
per 1 mol of | −84.05 | – | – | – |
per 1 mol of | −336.2 | – | – | – |
per 1 mol of | −56.03 | – | – | – |
Changes in aqueous solution (1)
- Reaction of potassium hexacyanidoferrate(II) and hydrogen iodide◆
ΔrG −55.8 kJ/mol K 5.97 × 109 pK −9.78 - K4[Fe(CN)6]Ionized aqueous solution + 6HIIonized aqueous solution4KIIonized aqueous solution + FeI2Ionized aqueous solution + 6HCNUn-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 | 97.9 | −55.8 | 515.5 | – |
per 1 mol of | 97.9 | −55.8 | 515.5 | – |
per 1 mol of | 16.3 | −9.30 | 85.92 | – |
per 1 mol of | 24.5 | −13.9 | 128.9 | – |
per 1 mol of | 97.9 | −55.8 | 515.5 | – |
per 1 mol of | 16.3 | −9.30 | 85.92 | – |
Changes in aqueous solution (2)
- Reaction of potassium hexacyanidoferrate(II) and hydrogen iodide◆
ΔrG 260.4 kJ/mol K 0.24 × 10−45 pK 45.62 - K4[Fe(CN)6]Ionized aqueous solution + 6HIIonized aqueous solution4KIIonized aqueous solution + FeI2Ionized aqueous solution + 6HCNIonized 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 | 358.9 | 260.4 | 331.9 | – |
per 1 mol of | 358.9 | 260.4 | 331.9 | – |
per 1 mol of | 59.82 | 43.40 | 55.32 | – |
per 1 mol of | 89.72 | 65.10 | 82.97 | – |
per 1 mol of | 358.9 | 260.4 | 331.9 | – |
per 1 mol of | 59.82 | 43.40 | 55.32 | – |
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 |
|---|---|---|---|---|
| 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] |
| HI (g) | 26.48[1] | 1.70[1] | 206.594[1] | 29.158[1] |
| HI (ai) | -55.19[1] | -51.57[1] | 111.3[1] | -142.3[1] |
* (cr):Crystalline solid, (ai):Ionized aqueous solution, (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 |
|---|---|---|---|---|
| KI (cr) | -327.900[1] | -324.892[1] | 106.32[1] | 52.93[1] |
| KI (g) | -125.5[1] | -166.1[1] | 258.3[1] | 37.11[1] |
| KI (ai) | -307.57[1] | -334.85[1] | 213.8[1] | -120.5[1] |
| FeI2 (cr) | -113.0[1] | – | – | – |
| FeI2 (g) | 60.7[1] | – | – | – |
| FeI2 (ai) | -199.6[1] | -182.05[1] | 84.9[1] | – |
| HCN (l) | 108.87[1] | 124.97[1] | 112.84[1] | 70.63[1] |
| HCN (g) | 135.1[1] | 124.7[1] | 201.78[1] | 35.86[1] |
| HCN (ai) | 150.6[1] | 172.4[1] | 94.1[1] | – |
| HCN (ao) | 107.1[1] | 119.7[1] | 124.7[1] | – |
* (cr):Crystalline solid, (g):Gas, (ai):Ionized aqueous solution, (l):Liquid, (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°, -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°, 26.48 kJ · mol−1
- ^ ΔfG°, 1.70 kJ · mol−1
- ^ S°, 206.594 J · K−1 · mol−1
- ^ Cp°, 29.158 J · K−1 · mol−1
- ^ ΔfH°, -55.19 kJ · mol−1
- ^ ΔfG°, -51.57 kJ · mol−1
- ^ S°, 111.3 J · K−1 · mol−1
- ^ Cp°, -142.3 J · K−1 · mol−1
- ^ ΔfH°, -327.900 kJ · mol−1
- ^ ΔfG°, -324.892 kJ · mol−1
- ^ S°, 106.32 J · K−1 · mol−1
- ^ Cp°, 52.93 J · K−1 · mol−1
- ^ ΔfH°, -125.5 kJ · mol−1
- ^ ΔfG°, -166.1 kJ · mol−1
- ^ S°, 258.3 J · K−1 · mol−1
- ^ Cp°, 37.11 J · K−1 · mol−1
- ^ ΔfH°, -307.57 kJ · mol−1
- ^ ΔfG°, -334.85 kJ · mol−1
- ^ S°, 213.8 J · K−1 · mol−1
- ^ Cp°, -120.5 J · K−1 · mol−1
- ^ ΔfH°, -113.0 kJ · mol−1
- ^ ΔfH°, 60.7 kJ · mol−1
- ^ ΔfH°, -199.6 kJ · mol−1
- ^ ΔfG°, -182.05 kJ · mol−1
- ^ S°, 84.9 J · K−1 · mol−1
- ^ ΔfH°, 108.87 kJ · mol−1
- ^ ΔfG°, 124.97 kJ · mol−1
- ^ S°, 112.84 J · K−1 · mol−1
- ^ Cp°, 70.63 J · K−1 · mol−1
- ^ ΔfH°, 135.1 kJ · mol−1
- ^ ΔfG°, 124.7 kJ · mol−1
- ^ S°, 201.78 J · K−1 · mol−1
- ^ Cp°, 35.86 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
- ^ ΔfH°, 107.1 kJ · mol−1
- ^ ΔfG°, 119.7 kJ · mol−1
- ^ S°, 124.7 J · K−1 · mol−1