2Na+ + 2HCrO4− → Na2Cr2O7 + H2O
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- Reaction of sodium ion and hydrogenchromate ion
The reaction of sodium ion and hydrogenchromate ion yields sodium dichromate and water. This reaction is an acid-base reaction and is classified as follows:
Table of contents
Reaction data
Chemical equation
- Reaction of sodium ion and hydrogenchromate ion
General equation
- Reaction of cation and anion
- CationLewis acid + AnionLewis base ⟶ ProductLewis conjugate + (H2O)
Oxidation state of each atom
- Reaction of sodium ion and hydrogenchromate ion
Reactants
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| Na+ | Sodium ion | 2 | Lewis acid | Cation |
| HCrO4− | Hydrogenchromate ion | 2 | Lewis base | Anion |
Products
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| Na2Cr2O7 | Sodium dichromate | 1 | Lewis conjugate | – |
| H2O | Water | 1 | – | Water |
Thermodynamic changes
Changes in standard condition
- Reaction of sodium ion and hydrogenchromate ion◆
ΔrG −8.8 kJ/mol K 3.48 × 101 pK −1.54
| 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 | −19.9 | −8.8 | −36.4 | – |
per 1 mol of Sodium ion | −9.95 | −4.4 | −18.2 | – |
per 1 mol of Hydrogenchromate ion | −9.95 | −4.4 | −18.2 | – |
per 1 mol of | −19.9 | −8.8 | −36.4 | – |
per 1 mol of | −19.9 | −8.8 | −36.4 | – |
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 |
|---|---|---|---|---|
| Na+ (g) | 609.358[1] | – | – | – |
| Na+ (ao) | -240.12[1] | -261.905[1] | 59.0[1] | 46.4[1] |
| HCrO4− (ao) | -878.2[1] | -764.7[1] | 184.1[1] | – |
* (g):Gas, (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 |
|---|---|---|---|---|
| Na2Cr2O7 (cr) | -1978.6[1] | – | – | – |
| Na2Cr2O7 (ai) | -1970.7[1] | -1824.9[1] | 379.9[1] | – |
| Na2Cr2O7 (cr) 2 hydrate | -2574.8[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°, 609.358 kJ · mol−1
- ^ ΔfH°, -240.12 kJ · mol−1
- ^ ΔfG°, -261.905 kJ · mol−1
- ^ S°, 59.0 J · K−1 · mol−1
- ^ Cp°, 46.4 J · K−1 · mol−1
- ^ ΔfH°, -878.2 kJ · mol−1
- ^ ΔfG°, -764.7 kJ · mol−1
- ^ S°, 184.1 J · K−1 · mol−1
- ^ ΔfH°, -1978.6 kJ · mol−1
- ^ ΔfH°, -1970.7 kJ · mol−1
- ^ ΔfG°, -1824.9 kJ · mol−1
- ^ S°, 379.9 J · K−1 · mol−1
- ^ ΔfH°, -2574.8 kJ · 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