KSCN + HI → KI + HSCN
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The reaction of potassium thiocyanate and hydrogen iodide yields potassium iodide and thiocyanic acid. This reaction is an acid-base reaction and is classified as follows:
Table of contents
Reaction data
Chemical equation
- Reaction of potassium thiocyanate 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 thiocyanate and hydrogen iodide
Reactants
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| KSCN | Potassium thiocyanate | 1 | Brønsted base | Salt of weak acid |
| HI | Hydrogen iodide | 1 | Brønsted acid | Strong acid |
Products
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| KI | Potassium iodide | 1 | Conjugate base | Salt of strong acid |
| HSCN | Thiocyanic acid | 1 | Conjugate acid | Weak acid |
Thermodynamic changes
Changes in aqueous solution (1)
- Reaction of potassium thiocyanate and hydrogen iodide◆
ΔrG 4.84 kJ/mol K 0.14 × 100 pK 0.85
| 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 | – | 4.84 | – | – |
per 1 mol of | – | 4.84 | – | – |
per 1 mol of | – | 4.84 | – | – |
per 1 mol of | – | 4.84 | – | – |
per 1 mol of | – | 4.84 | – | – |
Changes in aqueous solution (2)
- Reaction of potassium thiocyanate and hydrogen iodide◆
ΔrG −0.01 kJ/mol K 1.00 × 100 pK −0.00
| 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 | 0.00 | −0.01 | −0.1 | 0.0 |
per 1 mol of | 0.00 | −0.0100 | −0.10 | 0.0 |
per 1 mol of | 0.00 | −0.0100 | −0.10 | 0.0 |
per 1 mol of | 0.00 | −0.0100 | −0.10 | 0.0 |
per 1 mol of | 0.00 | −0.0100 | −0.10 | 0.0 |
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 |
|---|---|---|---|---|
| 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] |
| 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] |
| HSCN (ai) | 76.44[1] | 92.71[1] | 144.3[1] | -40.2[1] |
| HSCN (ao) | – | 97.56[1] | – | – |
* (cr):Crystalline solid, (g):Gas, (ai):Ionized aqueous solution, (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°, -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°, 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°, 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