2KI + 2H2SO4 🔥→ K2SO4 + I2 + SO2↑ + 2H2O
Last updated:
- Reaction of potassium iodide and sulfuric acid
The reaction of potassium iodide and sulfuric acid yields potassium sulfate, , sulfur dioxide, and water (Other reactions are here). This reaction is an oxidation-reduction reaction and is classified as follows:
Table of contents
Reaction data
Chemical equation
- Reaction of potassium iodide and sulfuric acid
General equation
- Reaction of oxidizable species and reducible species
- Oxidizable speciesReducing agent + Reducible speciesOxidizing agent🔥⟶ ProductOxidation product + ProductReduction product
Oxidation state of each atom
- Reaction of potassium iodide and sulfuric acid
Reactants
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| KI | Potassium iodide | 2 | Reducing | Oxidizable |
| H2SO4 | Sulfuric acid | 2 | Oxidizing | Reducible |
Products
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| K2SO4 | Potassium sulfate | 1 | – | – |
| 1 | Oxidized | – | ||
| SO2 | Sulfur dioxide | 1 | Reduced | – |
| H2O | Water | 2 | – | – |
Thermodynamic changes
Changes in standard condition
- Reaction of potassium iodide and sulfuric acid◆
ΔrG −66.03 kJ/mol K 3.70 × 1011 pK −11.57
| 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 | −22.50 | −66.03 | 153.29 | −7.33 |
per 1 mol of | −11.25 | −33.02 | 76.645 | −3.67 |
per 1 mol of | −11.25 | −33.02 | 76.645 | −3.67 |
per 1 mol of | −22.50 | −66.03 | 153.29 | −7.33 |
| −22.50 | −66.03 | 153.29 | −7.33 | |
per 1 mol of | −22.50 | −66.03 | 153.29 | −7.33 |
per 1 mol of | −11.25 | −33.02 | 76.645 | −3.67 |
Changes in aqueous solution (1)
- Reaction of potassium iodide and sulfuric acid◆
ΔrG 89.64 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 | 173.8 | 89.64 | 282.5 | – |
per 1 mol of | 86.90 | 44.82 | 141.3 | – |
per 1 mol of | 86.90 | 44.82 | 141.3 | – |
per 1 mol of | 173.8 | 89.64 | 282.5 | – |
| 173.8 | 89.64 | 282.5 | – | |
per 1 mol of | 173.8 | 89.64 | 282.5 | – |
per 1 mol of | 86.90 | 44.82 | 141.3 | – |
Changes in aqueous solution (2)
- Reaction of potassium iodide and sulfuric acid◆
ΔrG 89.16 kJ/mol K 0.24 × 10−15 pK 15.62
| 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 | 147.6 | 89.16 | 196.2 | – |
per 1 mol of | 73.80 | 44.58 | 98.10 | – |
per 1 mol of | 73.80 | 44.58 | 98.10 | – |
per 1 mol of | 147.6 | 89.16 | 196.2 | – |
| 147.6 | 89.16 | 196.2 | – | |
per 1 mol of | 147.6 | 89.16 | 196.2 | – |
per 1 mol of | 73.80 | 44.58 | 98.10 | – |
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 |
|---|---|---|---|---|
| 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] |
| H2SO4 (cr) | – | – | – | – |
| H2SO4 (l) | -813.989[1] | -690.003[1] | 156.904[1] | 138.91[1] |
| H2SO4 (ai) | -909.27[1] | -744.53[1] | 20.1[1] | -293[1] |
| H2SO4 (l) 1 hydrate | -1127.621[1] | -950.383[1] | 211.54[1] | 214.85[1] |
| H2SO4 (l) 2 hydrate | -1427.100[1] | -1199.650[1] | 276.40[1] | 260.83[1] |
| H2SO4 (l) 3 hydrate | -1720.402[1] | -1443.980[1] | 345.39[1] | 318.95[1] |
| H2SO4 (l) 4 hydrate | -2011.199[1] | -1685.863[1] | 414.59[1] | 382.21[1] |
| H2SO4 (l) 6.5 hydrate | -2733.256[1] | -2285.734[1] | 587.89[1] | 570.28[1] |
* (cr):Crystalline solid, (g):Gas, (ai):Ionized aqueous solution, (l):Liquid
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 |
|---|---|---|---|---|
| K2SO4 (cr) | -1437.79[1] | -1321.37[1] | 175.56[1] | 131.46[1] |
| K2SO4 (g) | -1096[1] | -1033[1] | 364[1] | 108.8[1] |
| K2SO4 (ai) | -1414.02[1] | -1311.07[1] | 225.1[1] | -251[1] |
| (cr) | 0[1] | 0[1] | 116.135[1] | 54.438[1] |
| (g) | 62.438[1] | 19.327[1] | 260.69[1] | 36.90[1] |
| (ao) | 22.6[1] | 16.40[1] | 137.2[1] | – |
| SO2 (l) | -320.5[1] | – | – | – |
| SO2 (g) | -296.830[1] | -300.194[1] | 248.22[1] | 39.87[1] |
| SO2 (ao) | -322.980[1] | -300.676[1] | 161.9[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, (g):Gas, (ai):Ionized aqueous solution, (ao):Un-ionized aqueous solution, (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°, -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°, -813.989 kJ · mol−1
- ^ ΔfG°, -690.003 kJ · mol−1
- ^ S°, 156.904 J · K−1 · mol−1
- ^ Cp°, 138.91 J · K−1 · mol−1
- ^ ΔfH°, -909.27 kJ · mol−1
- ^ ΔfG°, -744.53 kJ · mol−1
- ^ S°, 20.1 J · K−1 · mol−1
- ^ Cp°, -293. J · K−1 · mol−1
- ^ ΔfH°, -1127.621 kJ · mol−1
- ^ ΔfG°, -950.383 kJ · mol−1
- ^ S°, 211.54 J · K−1 · mol−1
- ^ Cp°, 214.85 J · K−1 · mol−1
- ^ ΔfH°, -1427.100 kJ · mol−1
- ^ ΔfG°, -1199.650 kJ · mol−1
- ^ S°, 276.40 J · K−1 · mol−1
- ^ Cp°, 260.83 J · K−1 · mol−1
- ^ ΔfH°, -1720.402 kJ · mol−1
- ^ ΔfG°, -1443.980 kJ · mol−1
- ^ S°, 345.39 J · K−1 · mol−1
- ^ Cp°, 318.95 J · K−1 · mol−1
- ^ ΔfH°, -2011.199 kJ · mol−1
- ^ ΔfG°, -1685.863 kJ · mol−1
- ^ S°, 414.59 J · K−1 · mol−1
- ^ Cp°, 382.21 J · K−1 · mol−1
- ^ ΔfH°, -2733.256 kJ · mol−1
- ^ ΔfG°, -2285.734 kJ · mol−1
- ^ S°, 587.89 J · K−1 · mol−1
- ^ Cp°, 570.28 J · K−1 · mol−1
- ^ ΔfH°, -1437.79 kJ · mol−1
- ^ ΔfG°, -1321.37 kJ · mol−1
- ^ S°, 175.56 J · K−1 · mol−1
- ^ Cp°, 131.46 J · K−1 · mol−1
- ^ ΔfH°, -1096. kJ · mol−1
- ^ ΔfG°, -1033. kJ · mol−1
- ^ S°, 364. J · K−1 · mol−1
- ^ Cp°, 108.8 J · K−1 · mol−1
- ^ ΔfH°, -1414.02 kJ · mol−1
- ^ ΔfG°, -1311.07 kJ · mol−1
- ^ S°, 225.1 J · K−1 · mol−1
- ^ Cp°, -251. J · K−1 · mol−1
- ^ ΔfH°, 0 kJ · mol−1
- ^ ΔfG°, 0 kJ · mol−1
- ^ S°, 116.135 J · K−1 · mol−1
- ^ Cp°, 54.438 J · K−1 · mol−1
- ^ ΔfH°, 62.438 kJ · mol−1
- ^ ΔfG°, 19.327 kJ · mol−1
- ^ S°, 260.69 J · K−1 · mol−1
- ^ Cp°, 36.90 J · K−1 · mol−1
- ^ ΔfH°, 22.6 kJ · mol−1
- ^ ΔfG°, 16.40 kJ · mol−1
- ^ S°, 137.2 J · K−1 · mol−1
- ^ ΔfH°, -320.5 kJ · mol−1
- ^ ΔfH°, -296.830 kJ · mol−1
- ^ ΔfG°, -300.194 kJ · mol−1
- ^ S°, 248.22 J · K−1 · mol−1
- ^ Cp°, 39.87 J · K−1 · mol−1
- ^ ΔfH°, -322.980 kJ · mol−1
- ^ ΔfG°, -300.676 kJ · mol−1
- ^ S°, 161.9 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