K2S + 2HSCN 🔥→ 2KSCN + H2S↑
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The reaction of potassium sulfide and thiocyanic acid yields potassium thiocyanate and hydrogen sulfide. This reaction is an acid-base reaction and is classified as follows:
Table of contents
Reaction data
Chemical equation
- Reaction of potassium sulfide and thiocyanic 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 sulfide and thiocyanic acid
Reactants
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| K2S | Potassium sulfide | 1 | 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 |
| H2S | Hydrogen sulfide | 1 | Conjugate acid | Volatile acid |
Thermodynamic changes
Changes in aqueous solution (1)
- Reaction of potassium sulfide and thiocyanic acid◆
ΔrG −119.4 kJ/mol K 8.28 × 1020 pK −20.92
| 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 | −53.9 | −119.4 | 220.6 | – |
per 1 mol of | −53.9 | −119.4 | 220.6 | – |
per 1 mol of | −26.9 | −59.70 | 110.3 | – |
per 1 mol of | −26.9 | −59.70 | 110.3 | – |
per 1 mol of | −53.9 | −119.4 | 220.6 | – |
Changes in aqueous solution (2)
- Reaction of potassium sulfide and thiocyanic acid◆
ΔrG −113.7 kJ/mol K 8.31 × 1019 pK −19.92
| 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 | −73.0 | −113.7 | 136 | – |
per 1 mol of | −73.0 | −113.7 | 136 | – |
per 1 mol of | −36.5 | −56.85 | 68.0 | – |
per 1 mol of | −36.5 | −56.85 | 68.0 | – |
per 1 mol of | −73.0 | −113.7 | 136 | – |
Changes in aqueous solution (3)
- Reaction of potassium sulfide and thiocyanic acid◆
ΔrG −129.1 kJ/mol K 4.14 × 1022 pK −22.62
| 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 | – | −129.1 | – | – |
per 1 mol of | – | −129.1 | – | – |
per 1 mol of | – | −64.55 | – | – |
per 1 mol of | – | −64.55 | – | – |
per 1 mol of | – | −129.1 | – | – |
Changes in aqueous solution (4)
- Reaction of potassium sulfide and thiocyanic acid◆
ΔrG −123.4 kJ/mol K 4.16 × 1021 pK −21.62
| 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 | – | −123.4 | – | – |
per 1 mol of | – | −123.4 | – | – |
per 1 mol of | – | −61.70 | – | – |
per 1 mol of | – | −61.70 | – | – |
per 1 mol of | – | −123.4 | – | – |
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 |
|---|---|---|---|---|
| K2S (cr) | -380.7[1] | -364.0[1] | 105[1] | – |
| K2S (ai) | -471.5[1] | -480.7[1] | 190.4[1] | – |
| K2S (cr) 2 hydrate | -975.3[1] | – | – | – |
| K2S (cr) 5 hydrate | -1871.5[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] |
| H2S (g) | -20.63[1] | -33.56[1] | 205.79[1] | 34.23[1] |
| H2S (ao) | -39.7[1] | -27.83[1] | 121[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°, -380.7 kJ · mol−1
- ^ ΔfG°, -364.0 kJ · mol−1
- ^ S°, 105. J · K−1 · mol−1
- ^ ΔfH°, -471.5 kJ · mol−1
- ^ ΔfG°, -480.7 kJ · mol−1
- ^ S°, 190.4 J · K−1 · mol−1
- ^ ΔfH°, -975.3 kJ · mol−1
- ^ ΔfH°, -1871.5 kJ · 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°, -20.63 kJ · mol−1
- ^ ΔfG°, -33.56 kJ · mol−1
- ^ S°, 205.79 J · K−1 · mol−1
- ^ Cp°, 34.23 J · K−1 · mol−1
- ^ ΔfH°, -39.7 kJ · mol−1
- ^ ΔfG°, -27.83 kJ · mol−1
- ^ S°, 121. J · K−1 · mol−1