2KOH + SO2 → K2SO3 + H2O
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The reaction of potassium hydroxide and sulfur dioxide yields potassium sulfite and water. This reaction is an acid-base reaction and is classified as follows:
- Reaction of base and acidic oxide
- Reaction of hydroxide base and acidic oxide
- Reaction of strong hydroxide base and weakly acidic oxide
Table of contents
Reaction data
Chemical equation
- Reaction of potassium hydroxide and sulfur dioxide
General equation
- Reaction of base and acidic oxide
- BaseLewis base + Acidic oxideLewis acid + H2O ⟶ Oxoacid saltLewis conjugate + (H2O)
- Reaction of hydroxide base and acidic oxide
- Hydroxide baseLewis base + Acidic oxideLewis acid ⟶ Oxoacid saltLewis conjugate + H2O
- Reaction of strong hydroxide base and weakly acidic oxide
- Strong hydroxide baseLewis base + Weakly acidic oxideLewis acid ⟶ Salt of weak acid and strong baseLewis conjugate + H2O
Oxidation state of each atom
- Reaction of potassium hydroxide and sulfur dioxide
Reactants
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| KOH | Potassium hydroxide | 2 | Lewis base | Base Hydroxide base Strong hydroxide base |
| SO2 | Sulfur dioxide | 1 | Lewis acid | Acidic oxide Weakly acidic oxide |
Products
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| K2SO3 | Potassium sulfite | 1 | Lewis conjugate | Oxoacid salt Salt of weak acid and strong base |
| H2O | Water | 1 | – | Water |
Thermodynamic changes
Changes in standard condition
- Reaction of potassium hydroxide and sulfur dioxide
| 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 | −265.0 | – | – | – |
per 1 mol of | −132.5 | – | – | – |
per 1 mol of | −265.0 | – | – | – |
per 1 mol of | −265.0 | – | – | – |
per 1 mol of | −265.0 | – | – | – |
Changes in aqueous solution
- Reaction of potassium hydroxide and sulfur dioxide◆
ΔrG −108.6 kJ/mol K 1.06 × 1019 pK −19.03
| 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 | −138.2 | −108.6 | −99 | – |
per 1 mol of | −69.10 | −54.30 | −50 | – |
per 1 mol of | −138.2 | −108.6 | −99 | – |
per 1 mol of | −138.2 | −108.6 | −99 | – |
per 1 mol of | −138.2 | −108.6 | −99 | – |
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 |
|---|---|---|---|---|
| KOH (cr) | -424.764[1] | -379.08[1] | 78.9[1] | 64.9[1] |
| KOH (g) | -231.0[1] | -232.6[1] | 238.3[1] | 49.20[1] |
| KOH (ai) | -482.37[1] | -440.50[1] | 91.6[1] | -126.8[1] |
| KOH (cr) 1 hydrate | -748.9[1] | -645.1[1] | 117.2[1] | – |
| KOH (cr) 2 hydrate | -1051.0[1] | -887.3[1] | 150.6[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] | – |
* (cr):Crystalline solid, (g):Gas, (ai):Ionized aqueous solution, (l):Liquid, (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 |
|---|---|---|---|---|
| K2SO3 (cr) | -1125.5[1] | – | – | – |
| K2SO3 (ai) | -1140.1[1] | -1053.1[1] | 176[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, (l):Liquid, (g):Gas
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°, -424.764 kJ · mol−1
- ^ ΔfG°, -379.08 kJ · mol−1
- ^ S°, 78.9 J · K−1 · mol−1
- ^ Cp°, 64.9 J · K−1 · mol−1
- ^ ΔfH°, -231.0 kJ · mol−1
- ^ ΔfG°, -232.6 kJ · mol−1
- ^ S°, 238.3 J · K−1 · mol−1
- ^ Cp°, 49.20 J · K−1 · mol−1
- ^ ΔfH°, -482.37 kJ · mol−1
- ^ ΔfG°, -440.50 kJ · mol−1
- ^ S°, 91.6 J · K−1 · mol−1
- ^ Cp°, -126.8 J · K−1 · mol−1
- ^ ΔfH°, -748.9 kJ · mol−1
- ^ ΔfG°, -645.1 kJ · mol−1
- ^ S°, 117.2 J · K−1 · mol−1
- ^ ΔfH°, -1051.0 kJ · mol−1
- ^ ΔfG°, -887.3 kJ · mol−1
- ^ S°, 150.6 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°, -1125.5 kJ · mol−1
- ^ ΔfH°, -1140.1 kJ · mol−1
- ^ ΔfG°, -1053.1 kJ · mol−1
- ^ S°, 176. 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