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9Co(OH)2 + 2KMnO4 → 3Co3O4 + 2MnO2 + K2O + 9H2O

9Co(OH)₂ + 2KMnO₄ → 3Co₃O₄ + 2MnO₂ + K₂O + 9H₂O

Last updated: June 13, 2022

Reaction of cobalt(II) hydroxide and potassium permanganate: 9Co(OH)₂Cobalt(II) hydroxide + 2KMnO₄Potassium permanganate
⟶
3Co₃O₄Cobalt(II,III) oxide + 2MnO₂Manganese(IV) oxide + K₂OPotassium oxide + 9H₂OWater

The reaction of cobalt(II) hydroxide and potassium permanganate yields cobalt(II,III) oxide, manganese(IV) oxide, potassium oxide, and water (Other reactions are here). This reaction is an oxidation-reduction reaction and is classified as follows:

Reaction of hardly oxidizable species and oxidizing species

Table of contents

Reaction data

Reactants

Chemical formula	Name	Coefficient	Type	Type in general equation
Co(OH)₂	Cobalt(II) hydroxide	9	Reducing	Hardly oxidizable
KMnO₄	Potassium permanganate	2	Oxidizing	Oxidizing

Products

Chemical formula	Name	Coefficient	Type	Type in general equation
Co₃O₄	Cobalt(II,III) oxide	3	Oxidized	–
MnO₂	Manganese(IV) oxide	2	Reduced	–
K₂O	Potassium oxide	1	–	–
H₂O	Water	9	–	–

Thermodynamic changes

Changes in standard condition (1)

Reaction of cobalt(II) hydroxide and potassium permanganate ◆ Δ_rG −182 kJ/mol K 7.67 × 10³¹ pK −31.89: 9Co(OH)₂Crystalline solidblue, precipitated + 2KMnO₄Crystalline solid
⟶
3Co₃O₄Crystalline solid + 2MnO₂Crystalline solid + K₂OCrystalline solid + 9H₂OLiquid

	Standard enthalpy of reaction Δ_rH° kJ · mol⁻¹	Standard Gibbs energy of reaction Δ_rG° kJ · mol⁻¹	Standard entropy of reaction Δ_rS° J · K⁻¹ · mol⁻¹	Standard heat capacity of reaction at constant pressure Δ_rC_p° J · K⁻¹ · mol⁻¹
per 1 mol of Equation	–	−182	–	–
per 1 mol of Cobalt(II) hydroxide	–	−20.2	–	–
per 1 mol of Potassium permanganate	–	−91.0	–	–
per 1 mol of Cobalt(II,III) oxide	–	−60.7	–	–
per 1 mol of Manganese(IV) oxide	–	−91.0	–	–
per 1 mol of Potassium oxide	–	−182	–	–
per 1 mol of Water	–	−20.2	–	–

Changes in standard condition (2)

Reaction of cobalt(II) hydroxide and potassium permanganate: 9Co(OH)₂Crystalline solidblue, precipitated + 2KMnO₄Crystalline solid
⟶
3Co₃O₄Crystalline solid + 2MnO₂Amorphous solidprecipitated + K₂OCrystalline solid + 9H₂OLiquid

	Standard enthalpy of reaction Δ_rH° kJ · mol⁻¹	Standard Gibbs energy of reaction Δ_rG° kJ · mol⁻¹	Standard entropy of reaction Δ_rS° J · K⁻¹ · mol⁻¹	Standard heat capacity of reaction at constant pressure Δ_rC_p° J · K⁻¹ · mol⁻¹
per 1 mol of Equation	–	–	–	–
per 1 mol of Cobalt(II) hydroxide	–	–	–	–
per 1 mol of Potassium permanganate	–	–	–	–
per 1 mol of Cobalt(II,III) oxide	–	–	–	–
per 1 mol of Manganese(IV) oxide	–	–	–	–
per 1 mol of Potassium oxide	–	–	–	–
per 1 mol of Water	–	–	–	–

Changes in standard condition (3)

Reaction of cobalt(II) hydroxide and potassium permanganate ◆ Δ_rG −145 kJ/mol K 2.53 × 10²⁵ pK −25.40: 9Co(OH)₂Crystalline solidpink, precipitated + 2KMnO₄Crystalline solid
⟶
3Co₃O₄Crystalline solid + 2MnO₂Crystalline solid + K₂OCrystalline solid + 9H₂OLiquid

	Standard enthalpy of reaction Δ_rH° kJ · mol⁻¹	Standard Gibbs energy of reaction Δ_rG° kJ · mol⁻¹	Standard entropy of reaction Δ_rS° J · K⁻¹ · mol⁻¹	Standard heat capacity of reaction at constant pressure Δ_rC_p° J · K⁻¹ · mol⁻¹
per 1 mol of Equation	−115	−145	82	–
per 1 mol of Cobalt(II) hydroxide	−12.8	−16.1	9.1	–
per 1 mol of Potassium permanganate	−57.5	−72.5	41	–
per 1 mol of Cobalt(II,III) oxide	−38.3	−48.3	27	–
per 1 mol of Manganese(IV) oxide	−57.5	−72.5	41	–
per 1 mol of Potassium oxide	−115	−145	82	–
per 1 mol of Water	−12.8	−16.1	9.1	–

Changes in standard condition (4)

Reaction of cobalt(II) hydroxide and potassium permanganate: 9Co(OH)₂Crystalline solidpink, precipitated + 2KMnO₄Crystalline solid
⟶
3Co₃O₄Crystalline solid + 2MnO₂Amorphous solidprecipitated + K₂OCrystalline solid + 9H₂OLiquid

	Standard enthalpy of reaction Δ_rH° kJ · mol⁻¹	Standard Gibbs energy of reaction Δ_rG° kJ · mol⁻¹	Standard entropy of reaction Δ_rS° J · K⁻¹ · mol⁻¹	Standard heat capacity of reaction at constant pressure Δ_rC_p° J · K⁻¹ · mol⁻¹
per 1 mol of Equation	−80	–	–	–
per 1 mol of Cobalt(II) hydroxide	−8.9	–	–	–
per 1 mol of Potassium permanganate	−40	–	–	–
per 1 mol of Cobalt(II,III) oxide	−27	–	–	–
per 1 mol of Manganese(IV) oxide	−40	–	–	–
per 1 mol of Potassium oxide	−80	–	–	–
per 1 mol of Water	−8.9	–	–	–

Changes in standard condition (5)

Reaction of cobalt(II) hydroxide and potassium permanganate ◆ Δ_rG −110 kJ/mol K 1.87 × 10¹⁹ pK −19.27: 9Co(OH)₂Crystalline solidpink, precipitated, aged + 2KMnO₄Crystalline solid
⟶
3Co₃O₄Crystalline solid + 2MnO₂Crystalline solid + K₂OCrystalline solid + 9H₂OLiquid

	Standard enthalpy of reaction Δ_rH° kJ · mol⁻¹	Standard Gibbs energy of reaction Δ_rG° kJ · mol⁻¹	Standard entropy of reaction Δ_rS° J · K⁻¹ · mol⁻¹	Standard heat capacity of reaction at constant pressure Δ_rC_p° J · K⁻¹ · mol⁻¹
per 1 mol of Equation	–	−110	–	–
per 1 mol of Cobalt(II) hydroxide	–	−12.2	–	–
per 1 mol of Potassium permanganate	–	−55.0	–	–
per 1 mol of Cobalt(II,III) oxide	–	−36.7	–	–
per 1 mol of Manganese(IV) oxide	–	−55.0	–	–
per 1 mol of Potassium oxide	–	−110	–	–
per 1 mol of Water	–	−12.2	–	–

Changes in standard condition (6)

Reaction of cobalt(II) hydroxide and potassium permanganate: 9Co(OH)₂Crystalline solidpink, precipitated, aged + 2KMnO₄Crystalline solid
⟶
3Co₃O₄Crystalline solid + 2MnO₂Amorphous solidprecipitated + K₂OCrystalline solid + 9H₂OLiquid

	Standard enthalpy of reaction Δ_rH° kJ · mol⁻¹	Standard Gibbs energy of reaction Δ_rG° kJ · mol⁻¹	Standard entropy of reaction Δ_rS° J · K⁻¹ · mol⁻¹	Standard heat capacity of reaction at constant pressure Δ_rC_p° J · K⁻¹ · mol⁻¹
per 1 mol of Equation	–	–	–	–
per 1 mol of Cobalt(II) hydroxide	–	–	–	–
per 1 mol of Potassium permanganate	–	–	–	–
per 1 mol of Cobalt(II,III) oxide	–	–	–	–
per 1 mol of Manganese(IV) oxide	–	–	–	–
per 1 mol of Potassium oxide	–	–	–	–
per 1 mol of Water	–	–	–	–

Changes in aqueous solution (1)

Reaction of cobalt(II) hydroxide and potassium permanganate ◆ Δ_rG −452 kJ/mol K 1.54 × 10⁷⁹ pK −79.19: 9Co(OH)₂Un-ionized aqueous solution + 2KMnO₄Ionized aqueous solution
⟶
3Co₃O₄Crystalline solid + 2MnO₂Crystalline solid + K₂OCrystalline solid + 9H₂OLiquid

	Standard enthalpy of reaction Δ_rH° kJ · mol⁻¹	Standard Gibbs energy of reaction Δ_rG° kJ · mol⁻¹	Standard entropy of reaction Δ_rS° J · K⁻¹ · mol⁻¹	Standard heat capacity of reaction at constant pressure Δ_rC_p° J · K⁻¹ · mol⁻¹
per 1 mol of Equation	–	−452	–	–
per 1 mol of Cobalt(II) hydroxide	–	−50.2	–	–
per 1 mol of Potassium permanganate	–	−226	–	–
per 1 mol of Cobalt(II,III) oxide	–	−151	–	–
per 1 mol of Manganese(IV) oxide	–	−226	–	–
per 1 mol of Potassium oxide	–	−452	–	–
per 1 mol of Water	–	−50.2	–	–

Changes in aqueous solution (2)

Reaction of cobalt(II) hydroxide and potassium permanganate ◆ Δ_rG −197 kJ/mol K 3.26 × 10³⁴ pK −34.51: 9Co(OH)₂Crystalline solidblue, precipitated + 2KMnO₄Ionized aqueous solution
⟶
3Co₃O₄Crystalline solid + 2MnO₂Crystalline solid + K₂OCrystalline solid + 9H₂OLiquid

	Standard enthalpy of reaction Δ_rH° kJ · mol⁻¹	Standard Gibbs energy of reaction Δ_rG° kJ · mol⁻¹	Standard entropy of reaction Δ_rS° J · K⁻¹ · mol⁻¹	Standard heat capacity of reaction at constant pressure Δ_rC_p° J · K⁻¹ · mol⁻¹
per 1 mol of Equation	–	−197	–	–
per 1 mol of Cobalt(II) hydroxide	–	−21.9	–	–
per 1 mol of Potassium permanganate	–	−98.5	–	–
per 1 mol of Cobalt(II,III) oxide	–	−65.7	–	–
per 1 mol of Manganese(IV) oxide	–	−98.5	–	–
per 1 mol of Potassium oxide	–	−197	–	–
per 1 mol of Water	–	−21.9	–	–

Changes in aqueous solution (3)

Reaction of cobalt(II) hydroxide and potassium permanganate ◆ Δ_rG −159 kJ/mol K 7.17 × 10²⁷ pK −27.86: 9Co(OH)₂Crystalline solidpink, precipitated + 2KMnO₄Ionized aqueous solution
⟶
3Co₃O₄Crystalline solid + 2MnO₂Crystalline solid + K₂OCrystalline solid + 9H₂OLiquid

	Standard enthalpy of reaction Δ_rH° kJ · mol⁻¹	Standard Gibbs energy of reaction Δ_rG° kJ · mol⁻¹	Standard entropy of reaction Δ_rS° J · K⁻¹ · mol⁻¹	Standard heat capacity of reaction at constant pressure Δ_rC_p° J · K⁻¹ · mol⁻¹
per 1 mol of Equation	−202	−159	−162	–
per 1 mol of Cobalt(II) hydroxide	−22.4	−17.7	−18.0	–
per 1 mol of Potassium permanganate	−101	−79.5	−81.0	–
per 1 mol of Cobalt(II,III) oxide	−67.3	−53.0	−54.0	–
per 1 mol of Manganese(IV) oxide	−101	−79.5	−81.0	–
per 1 mol of Potassium oxide	−202	−159	−162	–
per 1 mol of Water	−22.4	−17.7	−18.0	–

Changes in aqueous solution (4)

Reaction of cobalt(II) hydroxide and potassium permanganate ◆ Δ_rG −125 kJ/mol K 7.93 × 10²¹ pK −21.90: 9Co(OH)₂Crystalline solidpink, precipitated, aged + 2KMnO₄Ionized aqueous solution
⟶
3Co₃O₄Crystalline solid + 2MnO₂Crystalline solid + K₂OCrystalline solid + 9H₂OLiquid

	Standard enthalpy of reaction Δ_rH° kJ · mol⁻¹	Standard Gibbs energy of reaction Δ_rG° kJ · mol⁻¹	Standard entropy of reaction Δ_rS° J · K⁻¹ · mol⁻¹	Standard heat capacity of reaction at constant pressure Δ_rC_p° J · K⁻¹ · mol⁻¹
per 1 mol of Equation	–	−125	–	–
per 1 mol of Cobalt(II) hydroxide	–	−13.9	–	–
per 1 mol of Potassium permanganate	–	−62.5	–	–
per 1 mol of Cobalt(II,III) oxide	–	−41.7	–	–
per 1 mol of Manganese(IV) oxide	–	−62.5	–	–
per 1 mol of Potassium oxide	–	−125	–	–
per 1 mol of Water	–	−13.9	–	–

Thermodynamic data of reactants

Chemical formula	Standard enthalpy of formation Δ_fH° kJ · mol⁻¹	Standard Gibbs energy of formation Δ_fG° kJ · mol⁻¹	Standard molar entropy S° J · K⁻¹ · mol⁻¹	Standard molar heat capacity at constant pressure C_p° J · K⁻¹ · mol⁻¹
Co(OH)₂ (cr) blue, precipitated	–	-450.1^[1]	–	–
Co(OH)₂ (cr) pink, precipitated	-539.7^[1]	-454.3^[1]	79^[1]	–
Co(OH)₂ (cr) pink, precipitated, aged	–	-458.1^[1]	–	–
Co(OH)₂ (ai)	-518.0^[1]	-369.0^[1]	-134^[1]	–
Co(OH)₂ (ao)	–	-421.7^[1]	–	–
KMnO₄ (cr)	-837.2^[1]	-737.6^[1]	171.71^[1]	117.57^[1]
KMnO₄ (ai)	-793.8^[1]	-730.5^[1]	293.7^[1]	-60.2^[1]

* (cr):Crystalline solid, (ai):Ionized aqueous solution, (ao):Un-ionized aqueous solution

Thermodynamic data of products

Chemical formula	Standard enthalpy of formation Δ_fH° kJ · mol⁻¹	Standard Gibbs energy of formation Δ_fG° kJ · mol⁻¹	Standard molar entropy S° J · K⁻¹ · mol⁻¹	Standard molar heat capacity at constant pressure C_p° J · K⁻¹ · mol⁻¹
Co₃O₄ (cr)	-891^[1]	-774^[1]	102.5^[1]	123.4^[1]
MnO₂ (cr)	-520.03^[1]	-465.14^[1]	53.05^[1]	54.14^[1]
MnO₂ (am) precipitated	-502.5^[1]	–	–	–
K₂O (cr)	-361.5^[1]	-322.1^[2]	94.1^[2]	83.7^[2]
K₂O (g)	-63^[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, (am):Amorphous solid, (g):Gas, (l):Liquid

References

List of references

1
Janiel J. Reed (1989)
The NBS Tables of Chemical Thermodynamic Properties: Selected Values for Inorganic and C1 and C2 Organic Substances in SI Units
https://doi.org/10.18434/M32124
National Institute of Standards and Technology (NIST)
Citation list
2
James G. Speight (2017)
Lange's Handbook of Chemistry, 17th edition
https://www.accessengineeringlibrary.com/content/book/9781259586095
McGraw Hill Education
- Amazon
Citation list
- ^ Δ_fG°, -322.1 kJ · mol⁻¹ - p.280
- ^ S°, 94.1 J · K⁻¹ · mol⁻¹ - p.280
- ^ C_p°, 83.7 J · K⁻¹ · mol⁻¹ - p.280

Δ_rG	−182 kJ/mol
K	7.67 × 10³¹
pK	−31.89

Δ_rG	−145 kJ/mol
K	2.53 × 10²⁵
pK	−25.40

Δ_rG	−110 kJ/mol
K	1.87 × 10¹⁹
pK	−19.27

Δ_rG	−452 kJ/mol
K	1.54 × 10⁷⁹
pK	−79.19

9Co(OH)2 + 2KMnO4 → 3Co3O4 + 2MnO2 + K2O + 9H2O

Reaction data

Chemical equation

General equation

Oxidation state of each atom