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Chemical reactions
2NaHSO4 + Co(OH)2 → Na2SO4 + CoSO4 + 2H2O

2NaHSO₄ + Co(OH)₂ → Na₂SO₄ + CoSO₄ + 2H₂O

Last updated: June 13, 2022

Reaction of sodium hydrogensulfate and cobalt(II) hydroxide: 2NaHSO₄Sodium hydrogensulfate + Co(OH)₂Cobalt(II) hydroxide
⟶
Na₂SO₄Sodium sulfate + CoSO₄Cobalt(II) sulfate + 2H₂OWater

The reaction of sodium hydrogensulfate and cobalt(II) hydroxide yields sodium sulfate, cobalt(II) sulfate, and water. This reaction is an acid-base reaction and is classified as follows:

Table of contents

Reaction data

Reactants

Chemical formula	Name	Coefficient	Type	Type in general equation
NaHSO₄	Sodium hydrogensulfate	2	Brønsted acid	Acid salt
Co(OH)₂	Cobalt(II) hydroxide	1	Brønsted base	Base Hydroxide base

Products

Chemical formula	Name	Coefficient	Type	Type in general equation
Na₂SO₄	Sodium sulfate	1	Conjugate base	Salt
CoSO₄	Cobalt(II) sulfate	1	Conjugate base	Salt
H₂O	Water	2	– Conjugate acid	Water

Thermodynamic changes

Changes in standard condition (1)

Reaction of sodium hydrogensulfate and cobalt(II) hydroxide ◆ Δ_rG −91.0 kJ/mol K 8.76 × 10¹⁵ pK −15.94: 2NaHSO₄Crystalline solid + Co(OH)₂Crystalline solidblue, precipitated
⟶
Na₂SO₄Crystalline solidorthorhombic + CoSO₄Crystalline solid + 2H₂OLiquid

	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	–	−91.0	–	–
per 1 mol of Sodium hydrogensulfate	–	−45.5	–	–
per 1 mol of Cobalt(II) hydroxide	–	−91.0	–	–
per 1 mol of Sodium sulfate	–	−91.0	–	–
per 1 mol of Cobalt(II) sulfate	–	−91.0	–	–
per 1 mol of Water	–	−45.5	–	–

Changes in standard condition (2)

Reaction of sodium hydrogensulfate and cobalt(II) hydroxide: 2NaHSO₄Crystalline solid + Co(OH)₂Crystalline solidblue, precipitated
⟶
Na₂SO₄Crystalline solidmetastable + CoSO₄Crystalline solid + 2H₂OLiquid

	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 Sodium hydrogensulfate	–	–	–	–
per 1 mol of Cobalt(II) hydroxide	–	–	–	–
per 1 mol of Sodium sulfate	–	–	–	–
per 1 mol of Cobalt(II) sulfate	–	–	–	–
per 1 mol of Water	–	–	–	–

Changes in standard condition (3)

Reaction of sodium hydrogensulfate and cobalt(II) hydroxide ◆ Δ_rG −86.8 kJ/mol K 1.61 × 10¹⁵ pK −15.21: 2NaHSO₄Crystalline solid + Co(OH)₂Crystalline solidpink, precipitated
⟶
Na₂SO₄Crystalline solidorthorhombic + CoSO₄Crystalline solid + 2H₂OLiquid

	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	−56.3	−86.8	102	–
per 1 mol of Sodium hydrogensulfate	−28.1	−43.4	51.0	–
per 1 mol of Cobalt(II) hydroxide	−56.3	−86.8	102	–
per 1 mol of Sodium sulfate	−56.3	−86.8	102	–
per 1 mol of Cobalt(II) sulfate	−56.3	−86.8	102	–
per 1 mol of Water	−28.1	−43.4	51.0	–

Changes in standard condition (4)

Reaction of sodium hydrogensulfate and cobalt(II) hydroxide: 2NaHSO₄Crystalline solid + Co(OH)₂Crystalline solidpink, precipitated
⟶
Na₂SO₄Crystalline solidmetastable + CoSO₄Crystalline solid + 2H₂OLiquid

	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	–	–	108	–
per 1 mol of Sodium hydrogensulfate	–	–	54.0	–
per 1 mol of Cobalt(II) hydroxide	–	–	108	–
per 1 mol of Sodium sulfate	–	–	108	–
per 1 mol of Cobalt(II) sulfate	–	–	108	–
per 1 mol of Water	–	–	54.0	–

Changes in standard condition (5)

Reaction of sodium hydrogensulfate and cobalt(II) hydroxide ◆ Δ_rG −83.0 kJ/mol K 3.48 × 10¹⁴ pK −14.54: 2NaHSO₄Crystalline solid + Co(OH)₂Crystalline solidpink, precipitated, aged
⟶
Na₂SO₄Crystalline solidorthorhombic + CoSO₄Crystalline solid + 2H₂OLiquid

	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	–	−83.0	–	–
per 1 mol of Sodium hydrogensulfate	–	−41.5	–	–
per 1 mol of Cobalt(II) hydroxide	–	−83.0	–	–
per 1 mol of Sodium sulfate	–	−83.0	–	–
per 1 mol of Cobalt(II) sulfate	–	−83.0	–	–
per 1 mol of Water	–	−41.5	–	–

Changes in standard condition (6)

Reaction of sodium hydrogensulfate and cobalt(II) hydroxide: 2NaHSO₄Crystalline solid + Co(OH)₂Crystalline solidpink, precipitated, aged
⟶
Na₂SO₄Crystalline solidmetastable + CoSO₄Crystalline solid + 2H₂OLiquid

	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 Sodium hydrogensulfate	–	–	–	–
per 1 mol of Cobalt(II) hydroxide	–	–	–	–
per 1 mol of Sodium sulfate	–	–	–	–
per 1 mol of Cobalt(II) sulfate	–	–	–	–
per 1 mol of Water	–	–	–	–

Changes in aqueous solution (1)

Reaction of sodium hydrogensulfate and cobalt(II) hydroxide ◆ Δ_rG −67.6 kJ/mol K 6.97 × 10¹¹ pK −11.84: 2NaHSO₄Ionized aqueous solution + Co(OH)₂Un-ionized aqueous solution
⟶
Na₂SO₄Ionized aqueous solution + CoSO₄Crystalline solid + 2H₂OLiquid

	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	–	−67.6	–	–
per 1 mol of Sodium hydrogensulfate	–	−33.8	–	–
per 1 mol of Cobalt(II) hydroxide	–	−67.6	–	–
per 1 mol of Sodium sulfate	–	−67.6	–	–
per 1 mol of Cobalt(II) sulfate	–	−67.6	–	–
per 1 mol of Water	–	−33.8	–	–

Changes in aqueous solution (2)

Reaction of sodium hydrogensulfate and cobalt(II) hydroxide ◆ Δ_rG −39.2 kJ/mol K 7.37 × 10⁶ pK −6.87: 2NaHSO₄Ionized aqueous solution + Co(OH)₂Crystalline solidblue, precipitated
⟶
Na₂SO₄Ionized aqueous solution + CoSO₄Crystalline solid + 2H₂OLiquid

	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	–	−39.2	–	–
per 1 mol of Sodium hydrogensulfate	–	−19.6	–	–
per 1 mol of Cobalt(II) hydroxide	–	−39.2	–	–
per 1 mol of Sodium sulfate	–	−39.2	–	–
per 1 mol of Cobalt(II) sulfate	–	−39.2	–	–
per 1 mol of Water	–	−19.6	–	–

Changes in aqueous solution (3)

Reaction of sodium hydrogensulfate and cobalt(II) hydroxide ◆ Δ_rG −35.0 kJ/mol K 1.35 × 10⁶ pK −6.13: 2NaHSO₄Ionized aqueous solution + Co(OH)₂Crystalline solidpink, precipitated
⟶
Na₂SO₄Ionized aqueous solution + CoSO₄Crystalline solid + 2H₂OLiquid

	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	−54.9	−35.0	−65	–
per 1 mol of Sodium hydrogensulfate	−27.4	−17.5	−33	–
per 1 mol of Cobalt(II) hydroxide	−54.9	−35.0	−65	–
per 1 mol of Sodium sulfate	−54.9	−35.0	−65	–
per 1 mol of Cobalt(II) sulfate	−54.9	−35.0	−65	–
per 1 mol of Water	−27.4	−17.5	−33	–

Changes in aqueous solution (4)

Reaction of sodium hydrogensulfate and cobalt(II) hydroxide ◆ Δ_rG −31.2 kJ/mol K 2.92 × 10⁵ pK −5.47: 2NaHSO₄Ionized aqueous solution + Co(OH)₂Crystalline solidpink, precipitated, aged
⟶
Na₂SO₄Ionized aqueous solution + CoSO₄Crystalline solid + 2H₂OLiquid

	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	–	−31.2	–	–
per 1 mol of Sodium hydrogensulfate	–	−15.6	–	–
per 1 mol of Cobalt(II) hydroxide	–	−31.2	–	–
per 1 mol of Sodium sulfate	–	−31.2	–	–
per 1 mol of Cobalt(II) sulfate	–	−31.2	–	–
per 1 mol of Water	–	−15.6	–	–

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
NaHSO₄ (cr)	-1125.5^[1]	-992.8^[1]	113.0^[1]	–
NaHSO₄ (ai)	-1127.46^[1]	-1017.80^[1]	190.8^[1]	-38^[1]
NaHSO₄ (cr) 1 hydrate	-1421.7^[1]	-1231.6^[1]	155^[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]	–	–

* (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
Na₂SO₄ (cr) orthorhombic	-1387.08^[1]	-1270.16^[1]	149.58^[1]	128.20^[1]
Na₂SO₄ (cr) metastable	–	–	154.934^[1]	129.29^[1]
Na₂SO₄ (ai)	-1389.51^[1]	-1268.36^[1]	138.1^[1]	-201^[1]
Na₂SO₄ (cr) 10 hydrate	-4327.26^[1]	-3646.85^[1]	592.0^[1]	–
CoSO₄ (cr)	-888.3^[1]	-782.3^[1]	118.0^[1]	–
CoSO₄ (ai)	-967.3^[1]	-799.1^[1]	-92^[1]	–
CoSO₄ (cr) 6 hydrate	-2683.6^[1]	-2235.36^[1]	367.61^[1]	353.38^[1]
CoSO₄ (cr) 7 hydrate	-2979.93^[1]	-2473.42^[1]	406.06^[1]	390.49^[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

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

Δ_rG	−91.0 kJ/mol
K	8.76 × 10¹⁵
pK	−15.94

Δ_rG	−86.8 kJ/mol
K	1.61 × 10¹⁵
pK	−15.21

Δ_rG	−83.0 kJ/mol
K	3.48 × 10¹⁴
pK	−14.54

Δ_rG	−67.6 kJ/mol
K	6.97 × 10¹¹
pK	−11.84

2NaHSO4 + Co(OH)2 → Na2SO4 + CoSO4 + 2H2O