3HCl + 5CaCr2O7 + 25H+ → 3ClO2 + 5Cr3+ + 5Ca2+ + 5H2CrO4 + 9H2O
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- Reaction of hydrogen chloride and calcium dichromate under acidic condition
- 3HClHydrogen chloride + 5CaCr2O7Calcium dichromate + 25H+Hydrogen ion3ClO2Chlorine dioxide + 5Cr3+Chromium(III) ion + 5Ca2+Calcium ion + 5H2CrO4Chromic acid + 9H2OWater⟶
The reaction of hydrogen chloride, calcium dichromate, and hydrogen ion yields chlorine dioxide, chromium(III) ion, calcium ion, chromic acid, 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 hydrogen chloride and calcium dichromate under acidic condition
- 3HClHydrogen chloride + 5CaCr2O7Calcium dichromate + 25H+Hydrogen ion3ClO2Chlorine dioxide + 5Cr3+Chromium(III) ion + 5Ca2+Calcium ion + 5H2CrO4Chromic acid + 9H2OWater⟶
General equation
- Reaction of hardly oxidizable species and oxidizing species under acidic condition
- Hardly oxidizable speciesReducing agent + Oxidizing speciesOxidizing agent + H+Non-redox agent ⟶ ProductOxidation product + ProductReduction product + H2ONon-redox product
Oxidation state of each atom
- Reaction of hydrogen chloride and calcium dichromate under acidic condition
Reactants
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| HCl | Hydrogen chloride | 3 | Reducing | Hardly oxidizable |
| CaCr2O7 | Calcium dichromate | 5 | Oxidizing | Oxidizing under acidic condition |
| H+ | Hydrogen ion | 25 | – | Hydrogen ion |
Products
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| ClO2 | Chlorine dioxide | 3 | Oxidized | – |
| Cr3+ | Chromium(III) ion | 5 | Reduced | – |
| Ca2+ | Calcium ion | 5 | – | – |
| H2CrO4 | Chromic acid | 5 | – | – |
| H2O | Water | 9 | – | Water |
Thermodynamic changes
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 |
|---|---|---|---|---|
| HCl (g) | -92.307[1] | -95.299[1] | 186.908[1] | 29.12[1] |
| HCl (ai) | -167.159[1] | -131.228[1] | 56.5[1] | -136.4[1] |
| CaCr2O7 | – | – | – | – |
| H+ (g) | 1536.202[1] | – | – | – |
| H+ (ao) | 0[1] | 0[1] | 0[1] | 0[1] |
* (g):Gas, (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 |
|---|---|---|---|---|
| ClO2 (g) | 102.5[1] | 120.5[1] | 256.84[1] | 41.97[1] |
| ClO2 (ao) | 74.9[1] | 120.1[1] | 164.8[1] | – |
| Cr3+ (g) | 5648.4[1] | – | – | – |
| Ca2+ (g) | 1925.90[1] | – | – | – |
| Ca2+ (ao) | -542.83[1] | -553.58[1] | -53.1[1] | – |
| H2CrO4 | – | – | – | – |
| 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] |
* (g):Gas, (ao):Un-ionized aqueous solution, (cr):Crystalline solid, (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°, -92.307 kJ · mol−1
- ^ ΔfG°, -95.299 kJ · mol−1
- ^ S°, 186.908 J · K−1 · mol−1
- ^ Cp°, 29.12 J · K−1 · mol−1
- ^ ΔfH°, -167.159 kJ · mol−1
- ^ ΔfG°, -131.228 kJ · mol−1
- ^ S°, 56.5 J · K−1 · mol−1
- ^ Cp°, -136.4 J · K−1 · mol−1
- ^ ΔfH°, 1536.202 kJ · mol−1
- ^ ΔfH°, 0 kJ · mol−1
- ^ ΔfG°, 0 kJ · mol−1
- ^ S°, 0 J · K−1 · mol−1
- ^ Cp°, 0 J · K−1 · mol−1
- ^ ΔfH°, 102.5 kJ · mol−1
- ^ ΔfG°, 120.5 kJ · mol−1
- ^ S°, 256.84 J · K−1 · mol−1
- ^ Cp°, 41.97 J · K−1 · mol−1
- ^ ΔfH°, 74.9 kJ · mol−1
- ^ ΔfG°, 120.1 kJ · mol−1
- ^ S°, 164.8 J · K−1 · mol−1
- ^ ΔfH°, 5648.4 kJ · mol−1
- ^ ΔfH°, 1925.90 kJ · mol−1
- ^ ΔfH°, -542.83 kJ · mol−1
- ^ ΔfG°, -553.58 kJ · mol−1
- ^ S°, -53.1 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