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NH4F + H2SO4 → NH4HSO4 + HF↑

NH₄F + H₂SO₄ → NH₄HSO₄ + HF↑

Last updated: June 13, 2022

Reaction of ammonium fluoride and sulfuric acid: NH₄FAmmonium fluoride + H₂SO₄Sulfuric acid
⟶
NH₄HSO₄Ammonium hydrogensulfate + HF↑Hydrogen fluoride

The reaction of ammonium fluoride and sulfuric acid yields ammonium hydrogensulfate and hydrogen fluoride (Other reactions are here). 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
NH₄F	Ammonium fluoride	1	Brønsted base	Salt of weak acid Salt of volatile acid
H₂SO₄	Sulfuric acid	1	Brønsted acid	Strong acid Nonvolatile acid

Products

Chemical formula	Name	Coefficient	Type	Type in general equation
NH₄HSO₄	Ammonium hydrogensulfate	1	Conjugate base	Salt of strong acid Salt of non volatile acid
HF	Hydrogen fluoride	1	Conjugate acid	Weak acid Volatile acid

Thermodynamic changes

Changes in standard condition

Reaction of ammonium fluoride and sulfuric acid: NH₄FCrystalline solid + H₂SO₄Liquid
⟶
NH₄HSO₄Crystalline solid + HF↑Gas

	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	−20.1	–	–	–
per 1 mol of Ammonium fluoride	−20.1	–	–	–
per 1 mol of Sulfuric acid	−20.1	–	–	–
per 1 mol of Ammonium hydrogensulfate	−20.1	–	–	–
per 1 mol of Hydrogen fluoride	−20.1	–	–	–

Changes in aqueous solution (1)

Reaction of ammonium fluoride and sulfuric acid ◆ Δ_rG −5.8 kJ/mol K 1.04 × 10¹ pK −1.02: NH₄FIonized aqueous solution + H₂SO₄Ionized aqueous solution
⟶
NH₄HSO₄Ionized aqueous solution + HF↑Gas

	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	83.5	−5.8	299.3	345
per 1 mol of Ammonium fluoride	83.5	−5.8	299.3	345
per 1 mol of Sulfuric acid	83.5	−5.8	299.3	345
per 1 mol of Ammonium hydrogensulfate	83.5	−5.8	299.3	345
per 1 mol of Hydrogen fluoride	83.5	−5.8	299.3	345

Changes in aqueous solution (2)

Reaction of ammonium fluoride and sulfuric acid ◆ Δ_rG −29.41 kJ/mol K 1.42 × 10⁵ pK −5.15: NH₄FIonized aqueous solution + H₂SO₄Ionized aqueous solution
⟶
NH₄HSO₄Ionized aqueous solution + HF↑Un-ionized aqueous solution

	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	34.48	−29.41	214.2	–
per 1 mol of Ammonium fluoride	34.48	−29.41	214.2	–
per 1 mol of Sulfuric acid	34.48	−29.41	214.2	–
per 1 mol of Ammonium hydrogensulfate	34.48	−29.41	214.2	–
per 1 mol of Hydrogen fluoride	34.48	−29.41	214.2	–

Changes in aqueous solution (3)

Reaction of ammonium fluoride and sulfuric acid ◆ Δ_rG −29.41 kJ/mol K 1.42 × 10⁵ pK −5.15: NH₄FIonized aqueous solution + H₂SO₄Ionized aqueous solution
⟶
NH₄HSO₄Ionized aqueous solution + HF↑Un-ionized aqueous solution

	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	34.48	−29.41	214.2	–
per 1 mol of Ammonium fluoride	34.48	−29.41	214.2	–
per 1 mol of Sulfuric acid	34.48	−29.41	214.2	–
per 1 mol of Ammonium hydrogensulfate	34.48	−29.41	214.2	–
per 1 mol of Hydrogen fluoride	34.48	−29.41	214.2	–

Changes in aqueous solution (4)

Reaction of ammonium fluoride and sulfuric acid ◆ Δ_rG −11.38 kJ/mol K 9.86 × 10¹ pK −1.99: NH₄FIonized aqueous solution + H₂SO₄Ionized aqueous solution
⟶
NH₄HSO₄Ionized aqueous solution + HF↑Ionized aqueous solution

	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	21.93	−11.38	111.7	209
per 1 mol of Ammonium fluoride	21.93	−11.38	111.7	209
per 1 mol of Sulfuric acid	21.93	−11.38	111.7	209
per 1 mol of Ammonium hydrogensulfate	21.93	−11.38	111.7	209
per 1 mol of Hydrogen fluoride	21.93	−11.38	111.7	209

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
NH₄F (cr)	-463.96^[1]	-348.68^[1]	71.96^[1]	65.27^[1]
NH₄F (ai)	-465.14^[1]	-358.09^[1]	99.6^[1]	-26.8^[1]
H₂SO₄ (cr)	–	–	–	–
H₂SO₄ (l)	-813.989^[1]	-690.003^[1]	156.904^[1]	138.91^[1]
H₂SO₄ (ai)	-909.27^[1]	-744.53^[1]	20.1^[1]	-293^[1]
H₂SO₄ (l) 1 hydrate	-1127.621^[1]	-950.383^[1]	211.54^[1]	214.85^[1]
H₂SO₄ (l) 2 hydrate	-1427.100^[1]	-1199.650^[1]	276.40^[1]	260.83^[1]
H₂SO₄ (l) 3 hydrate	-1720.402^[1]	-1443.980^[1]	345.39^[1]	318.95^[1]
H₂SO₄ (l) 4 hydrate	-2011.199^[1]	-1685.863^[1]	414.59^[1]	382.21^[1]
H₂SO₄ (l) 6.5 hydrate	-2733.256^[1]	-2285.734^[1]	587.89^[1]	570.28^[1]

* (cr):Crystalline solid, (ai):Ionized aqueous solution, (l):Liquid

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
NH₄HSO₄ (cr)	-1026.96^[1]	–	–	–
NH₄HSO₄ (ai)	-1019.85^[1]	-835.21^[1]	245.2^[1]	-3.8^[1]
HF (l) x denotes undetermined zero point entropy	-299.78^[1]	–	75.40+x^[1]	–
HF (g)	-271.1^[1]	-273.2^[1]	173.779^[1]	29.133^[1]
HF (ai)	-332.63^[1]	-278.79^[1]	-13.8^[1]	-106.7^[1]
HF (ao)	-320.08^[1]	-296.82^[1]	88.7^[1]	–

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

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	−5.8 kJ/mol
K	1.04 × 10¹
pK	−1.02

Δ_rG	−29.41 kJ/mol
K	1.42 × 10⁵
pK	−5.15

Δ_rG	−29.41 kJ/mol
K	1.42 × 10⁵
pK	−5.15

Δ_rG	−11.38 kJ/mol
K	9.86 × 10¹
pK	−1.99

NH4F + H2SO4 → NH4HSO4 + HF↑

Reaction data

Chemical equation

General equation

Oxidation state of each atom