Mg(OH)2 → Mg2+ + 2OH−
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- Electrolytic dissociation of magnesium hydroxide
Electrolytic dissociation of magnesium hydroxide yields magnesium ion and hydroxide ion (Other reactions are here). This reaction is an acid-base reaction and is classified as follows:
Table of contents
Reaction data
Chemical equation
- Electrolytic dissociation of magnesium hydroxide
General equation
- Electrolytic dissociation of hydroxide base
- Hydroxide baseBrønsted base ⟶ CationConjugate acid + OH−
Oxidation state of each atom
- Electrolytic dissociation of magnesium hydroxide
Reactants
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| Mg(OH)2 | Magnesium hydroxide | 1 | Brønsted base | Hydroxide base |
Products
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| Mg2+ | Magnesium ion | 1 | Conjugate acid | Cation |
| OH− | Hydroxide ion | 2 | – | Hydroxide ion |
Thermodynamic changes
Changes in standard condition (1)
- Electrolytic dissociation of magnesium hydroxide◆
ΔrG 64.2 kJ/mol K 0.57 × 10−11 pK 11.25
| 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 | −2.30 | 64.2 | −222.8 | – |
per 1 mol of | −2.30 | 64.2 | −222.8 | – |
per 1 mol of Magnesium ion | −2.30 | 64.2 | −222.8 | – |
per 1 mol of Hydroxide ion | −1.15 | 32.1 | −111.4 | – |
Changes in standard condition (2)
- Electrolytic dissociation of magnesium hydroxide
- Mg(OH)2Amorphous solidprecipitatedMg2+Un-ionized aqueous solution + 2OH−Un-ionized aqueous solution⟶
| 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 | −6.3 | – | – | – |
per 1 mol of | −6.3 | – | – | – |
per 1 mol of Magnesium ion | −6.3 | – | – | – |
per 1 mol of Hydroxide ion | −3.1 | – | – | – |
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 |
|---|---|---|---|---|
| Mg(OH)2 (cr) | -924.54[1] | -833.51[1] | 63.18[1] | 77.03[1] |
| Mg(OH)2 (am) precipitated | -920.5[1] | – | – | – |
| Mg(OH)2 (g) | -561[1] | – | – | – |
| Mg(OH)2 (ai) | -926.84[1] | -769.4[1] | -159.4[1] | – |
* (cr):Crystalline solid, (am):Amorphous solid, (g):Gas, (ai):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 |
|---|---|---|---|---|
| Mg2+ (g) | 2348.504[1] | – | – | – |
| Mg2+ (ao) | -466.85[1] | -454.8[1] | -138.1[1] | – |
| OH− (g) | -143.5[1] | – | – | – |
| OH− (ao) | -229.994[1] | -157.244[1] | -10.75[1] | -148.5[1] |
* (g):Gas, (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°, -924.54 kJ · mol−1
- ^ ΔfG°, -833.51 kJ · mol−1
- ^ S°, 63.18 J · K−1 · mol−1
- ^ Cp°, 77.03 J · K−1 · mol−1
- ^ ΔfH°, -920.5 kJ · mol−1
- ^ ΔfH°, -561. kJ · mol−1
- ^ ΔfH°, -926.84 kJ · mol−1
- ^ ΔfG°, -769.4 kJ · mol−1
- ^ S°, -159.4 J · K−1 · mol−1
- ^ ΔfH°, 2348.504 kJ · mol−1
- ^ ΔfH°, -466.85 kJ · mol−1
- ^ ΔfG°, -454.8 kJ · mol−1
- ^ S°, -138.1 J · K−1 · mol−1
- ^ ΔfH°, -143.5 kJ · mol−1
- ^ ΔfH°, -229.994 kJ · mol−1
- ^ ΔfG°, -157.244 kJ · mol−1
- ^ S°, -10.75 J · K−1 · mol−1
- ^ Cp°, -148.5 J · K−1 · mol−1