2KCN + H2Cr2O7 → K2Cr2O7 + 2HCN
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The reaction of potassium cyanide and dichromic acid yields potassium dichromate 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 cyanide and dichromic acid
General equation
- Salt of volatile acidBrønsted base + Nonvolatile acidBrønsted acid ⟶ Salt of non volatile acidConjugate base + Volatile acidConjugate acid
Oxidation state of each atom
- Reaction of potassium cyanide and dichromic acid
Reactants
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| KCN | Potassium cyanide | 2 | Brønsted base | Salt of volatile acid |
| H2Cr2O7 | Dichromic acid | 1 | Brønsted acid | Nonvolatile acid |
Products
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| K2Cr2O7 | Potassium dichromate | 1 | Conjugate base | Salt of non volatile acid |
| HCN | Hydrogen cyanide | 2 | Conjugate acid | Volatile acid |
Thermodynamic changes
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 |
|---|---|---|---|---|
| KCN (cr) | -113.0[1] | -101.86[1] | 128.49[1] | 66.27[1] |
| KCN (g) | 90.8[1] | 64.17[1] | 261.90[1] | 52.34[1] |
| KCN (ai) | -101.7[1] | -110.9[1] | 196.6[1] | – |
| H2Cr2O7 | – | – | – | – |
* (cr):Crystalline solid, (g):Gas, (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 |
|---|---|---|---|---|
| K2Cr2O7 (cr) | -2061.5[1] | -1881.8[1] | 291.2[1] | 219.24[1] |
| K2Cr2O7 (ai) | -1994.9[1] | -1867.6[1] | 466.9[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, (ai):Ionized aqueous solution, (l):Liquid, (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°, -113.0 kJ · mol−1
- ^ ΔfG°, -101.86 kJ · mol−1
- ^ S°, 128.49 J · K−1 · mol−1
- ^ Cp°, 66.27 J · K−1 · mol−1
- ^ ΔfH°, 90.8 kJ · mol−1
- ^ ΔfG°, 64.17 kJ · mol−1
- ^ S°, 261.90 J · K−1 · mol−1
- ^ Cp°, 52.34 J · K−1 · mol−1
- ^ ΔfH°, -101.7 kJ · mol−1
- ^ ΔfG°, -110.9 kJ · mol−1
- ^ S°, 196.6 J · K−1 · mol−1
- ^ ΔfH°, -2061.5 kJ · mol−1
- ^ ΔfG°, -1881.8 kJ · mol−1
- ^ S°, 291.2 J · K−1 · mol−1
- ^ Cp°, 219.24 J · K−1 · mol−1
- ^ ΔfH°, -1994.9 kJ · mol−1
- ^ ΔfG°, -1867.6 kJ · mol−1
- ^ S°, 466.9 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