2KNO3 + 2HSCN 🔥→ 2KSCN + N2O5 + H2O
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The reaction of potassium nitrate and thiocyanic acid yields potassium thiocyanate, dinitrogen pentaoxide, and water. This reaction is an acid-base reaction and is classified as follows:
Table of contents
Reaction data
Chemical equation
- Reaction of potassium nitrate and thiocyanic acid
General equation
- Salt of volatile acidBrønsted base + Nonvolatile acidBrønsted acid ⟶ Salt of non volatile acidConjugate base + Volatile acidic oxide + H2OConjugate acid
Oxidation state of each atom
- Reaction of potassium nitrate and thiocyanic acid
Reactants
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| KNO3 | Potassium nitrate | 2 | Brønsted base | Salt of volatile acid |
| HSCN | Thiocyanic acid | 2 | Brønsted acid | Nonvolatile acid |
Products
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| KSCN | Potassium thiocyanate | 2 | Conjugate base | Salt of non volatile acid |
| N2O5 | Dinitrogen pentaoxide | 1 | – | Volatile acidic oxide |
| H2O | Water | 1 | Conjugate acid | Water |
Thermodynamic changes
Changes in aqueous solution (1)
- Reaction of potassium nitrate and thiocyanic acid◆
ΔrG 99.3 kJ/mol K 0.40 × 10−17 pK 17.40
| 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 | 85.8 | 99.3 | −44.5 | 391.8 |
per 1 mol of | 42.9 | 49.6 | −22.3 | 195.9 |
per 1 mol of | 42.9 | 49.6 | −22.3 | 195.9 |
per 1 mol of | 42.9 | 49.6 | −22.3 | 195.9 |
per 1 mol of | 85.8 | 99.3 | −44.5 | 391.8 |
per 1 mol of | 85.8 | 99.3 | −44.5 | 391.8 |
Changes in aqueous solution (2)
- Reaction of potassium nitrate and thiocyanic acid◆
ΔrG 89.6 kJ/mol K 0.20 × 10−15 pK 15.70
| 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 | – | 89.6 | – | – |
per 1 mol of | – | 44.8 | – | – |
per 1 mol of | – | 44.8 | – | – |
per 1 mol of | – | 44.8 | – | – |
per 1 mol of | – | 89.6 | – | – |
per 1 mol of | – | 89.6 | – | – |
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 |
|---|---|---|---|---|
| KNO3 (cr) | -494.63[1] | -394.86[1] | 133.05[1] | 96.40[1] |
| KNO3 (ai) | -459.74[1] | -394.53[1] | 248.9[1] | -64.9[1] |
| HSCN (ai) | 76.44[1] | 92.71[1] | 144.3[1] | -40.2[1] |
| HSCN (ao) | – | 97.56[1] | – | – |
* (cr):Crystalline solid, (ai):Ionized aqueous solution, (ao):Un-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 |
|---|---|---|---|---|
| KSCN (cr) | -200.16[1] | -178.31[1] | 124.26[1] | 88.53[1] |
| KSCN (ai) | -175.94[1] | -190.56[1] | 246.9[1] | -18.4[1] |
| N2O5 (cr) | -43.1[1] | 113.9[1] | 178.2[1] | 143.1[1] |
| N2O5 (g) | 11.3[1] | 115.1[1] | 355.7[1] | 84.5[1] |
| H2O (cr) | – | – | – | – |
| H2O (l) | -285.830[1] | -237.129[1] | 69.91[1] | 75.291[1] |
| H2O (g) | -241.818[1] | -228.572[1] | 188.825[1] | 33.577[1] |
* (cr):Crystalline solid, (ai):Ionized aqueous solution, (g):Gas, (l):Liquid
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°, -494.63 kJ · mol−1
- ^ ΔfG°, -394.86 kJ · mol−1
- ^ S°, 133.05 J · K−1 · mol−1
- ^ Cp°, 96.40 J · K−1 · mol−1
- ^ ΔfH°, -459.74 kJ · mol−1
- ^ ΔfG°, -394.53 kJ · mol−1
- ^ S°, 248.9 J · K−1 · mol−1
- ^ Cp°, -64.9 J · K−1 · mol−1
- ^ ΔfH°, 76.44 kJ · mol−1
- ^ ΔfG°, 92.71 kJ · mol−1
- ^ S°, 144.3 J · K−1 · mol−1
- ^ Cp°, -40.2 J · K−1 · mol−1
- ^ ΔfG°, 97.56 kJ · mol−1
- ^ ΔfH°, -200.16 kJ · mol−1
- ^ ΔfG°, -178.31 kJ · mol−1
- ^ S°, 124.26 J · K−1 · mol−1
- ^ Cp°, 88.53 J · K−1 · mol−1
- ^ ΔfH°, -175.94 kJ · mol−1
- ^ ΔfG°, -190.56 kJ · mol−1
- ^ S°, 246.9 J · K−1 · mol−1
- ^ Cp°, -18.4 J · K−1 · mol−1
- ^ ΔfH°, -43.1 kJ · mol−1
- ^ ΔfG°, 113.9 kJ · mol−1
- ^ S°, 178.2 J · K−1 · mol−1
- ^ Cp°, 143.1 J · K−1 · mol−1
- ^ ΔfH°, 11.3 kJ · mol−1
- ^ ΔfG°, 115.1 kJ · mol−1
- ^ S°, 355.7 J · K−1 · mol−1
- ^ Cp°, 84.5 J · K−1 · 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°, -241.818 kJ · mol−1
- ^ ΔfG°, -228.572 kJ · mol−1
- ^ S°, 188.825 J · K−1 · mol−1
- ^ Cp°, 33.577 J · K−1 · mol−1