2H2SO3 🔥→ S + 2H2O2 + SO2↑
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- Decomposition of sulfurous acid
Decomposition of sulfurous acid yields , , and sulfur dioxide (Other reactions are here). This reaction is an oxidation-reduction reaction and is classified as follows:
Table of contents
Reaction data
Chemical equation
- Decomposition of sulfurous acid
General equation
- Thermal decomposition with redox
- Thermally decomposable substanceSelf redox agent🔥⟶ ProductOxidation product + ProductReduction product
Oxidation state of each atom
- Decomposition of sulfurous acid
Reactants
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| H2SO3 | Sulfurous acid | 2 | Self redox agent | Thermally decomposable |
Products
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| 1 | Reduced | – | ||
| 2 | Oxidized | – | ||
| SO2 | Sulfur dioxide | 1 | – | – |
Thermodynamic changes
Changes in standard condition (1)
- Decomposition of sulfurous acid◆
ΔrG 507.37 kJ/mol K 0.13 × 10−88 pK 88.89
| 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 | 538.45 | 507.37 | 103.4 | – |
per 1 mol of | 269.23 | 253.69 | 51.70 | – |
| 538.45 | 507.37 | 103.4 | – | |
| 269.23 | 253.69 | 51.70 | – | |
per 1 mol of | 538.45 | 507.37 | 103.4 | – |
Changes in standard condition (2)
- Decomposition of sulfurous acid◆
ΔrG 506.88 kJ/mol K 0.16 × 10−88 pK 88.80
| 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 | 512.30 | 506.88 | 17.1 | – |
per 1 mol of | 256.15 | 253.44 | 8.55 | – |
| 512.30 | 506.88 | 17.1 | – | |
| 256.15 | 253.44 | 8.55 | – | |
per 1 mol of | 512.30 | 506.88 | 17.1 | – |
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 |
|---|---|---|---|---|
| H2SO3 (ao) | -608.81[1] | -537.81[1] | 232.2[1] | – |
* (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 |
|---|---|---|---|---|
| (cr) rhombic | 0[1] | 0[1] | 31.80[1] | 22.64[1] |
| (cr) monoclinic | 0.33[1] | – | – | – |
| (g) | 278.805[1] | 238.250[1] | 167.821[1] | 23.673[1] |
| (l) | -187.78[1] | -120.35[1] | 109.6[1] | 89.1[1] |
| (g) | -136.31[1] | -105.57[1] | 232.7[1] | 43.1[1] |
| (ao) | -191.17[1] | -134.03[1] | 143.9[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, (l):Liquid, (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°, -608.81 kJ · mol−1
- ^ ΔfG°, -537.81 kJ · mol−1
- ^ S°, 232.2 J · K−1 · mol−1
- ^ ΔfH°, 0 kJ · mol−1
- ^ ΔfG°, 0 kJ · mol−1
- ^ S°, 31.80 J · K−1 · mol−1
- ^ Cp°, 22.64 J · K−1 · mol−1
- ^ ΔfH°, 0.33 kJ · mol−1
- ^ ΔfH°, 278.805 kJ · mol−1
- ^ ΔfG°, 238.250 kJ · mol−1
- ^ S°, 167.821 J · K−1 · mol−1
- ^ Cp°, 23.673 J · K−1 · mol−1
- ^ ΔfH°, -187.78 kJ · mol−1
- ^ ΔfG°, -120.35 kJ · mol−1
- ^ S°, 109.6 J · K−1 · mol−1
- ^ Cp°, 89.1 J · K−1 · mol−1
- ^ ΔfH°, -136.31 kJ · mol−1
- ^ ΔfG°, -105.57 kJ · mol−1
- ^ S°, 232.7 J · K−1 · mol−1
- ^ Cp°, 43.1 J · K−1 · mol−1
- ^ ΔfH°, -191.17 kJ · mol−1
- ^ ΔfG°, -134.03 kJ · mol−1
- ^ S°, 143.9 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