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2KBr + H2SO4 → K2SO4 + 2HBr↑

The reaction of potassium bromide and sulfuric acid yields potassium sulfate and hydrogen bromide (Other reactions are here). This reaction is an acid-base reaction and is classified as follows:

Table of contents
  1. 1Reaction data
  2. 2Thermodynamic changes
  3. 3References
  4. 4Related reactions
  5. 5Related categories

Reaction data

Chemical equation

General equation

Oxidation state of each atom

Reactants

Chemical formulaNameCoefficientTypeType in general
equation
KBrPotassium bromide2
Brønsted base
Salt of volatile acid
H2SO4Sulfuric acid1
Brønsted acid
Nonvolatile acid

Products

Chemical formulaNameCoefficientTypeType in general
equation
K2SO4Potassium sulfate1
Conjugate base
Salt of non volatile acid
HBrHydrogen bromide2
Conjugate acid
Volatile acid

Thermodynamic changes

Changes in standard condition

Reaction of potassium bromide and sulfuric acid
ΔrG23.05 kJ/mol
K0.92 × 10−4
pK4.04
2KBrCrystalline solid + H2SO4Liquid
K2SO4Crystalline solid + 2HBrGas
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
91.0023.05224.25−53.77
per 1 mol of
45.5011.53112.13−26.89
per 1 mol of
91.0023.05224.25−53.77
per 1 mol of
91.0023.05224.25−53.77
per 1 mol of
45.5011.53112.13−26.89

Changes in aqueous solution (1)

Reaction of potassium bromide and sulfuric acid
ΔrG101.02 kJ/mol
K0.20 × 10−17
pK17.70
2KBrIonized aqueous solution + H2SO4Ionized aqueous solution
K2SO4Ionized aqueous solution + 2HBrGas
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
170.29101.02232.6340
per 1 mol of
85.14550.510116.3170
per 1 mol of
170.29101.02232.6340
per 1 mol of
170.29101.02232.6340
per 1 mol of
85.14550.510116.3170

Changes in aqueous solution (2)

Reaction of potassium bromide and sulfuric acid
ΔrG0.00 kJ/mol
K1.00 × 100
pK0.00
2KBrIonized aqueous solution + H2SO4Ionized aqueous solution
K2SO4Ionized aqueous solution + 2HBrIonized 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
−0.010.000.0−1
per 1 mol of
−0.005000.000.0−0.5
per 1 mol of
−0.01000.000.0−1
per 1 mol of
−0.01000.000.0−1
per 1 mol of
−0.005000.000.0−0.5

Thermodynamic data of reactants

Chemical formulaStandard 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
KBr (cr)-393.798[1]-380.66[1]95.90[1]52.30[1]
KBr (g)-180.08[1]-212.96[1]250.52[1]36.920[1]
KBr (ai)-373.92[1]-387.23[1]184.9[1]-120.1[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, (g):Gas, (ai):Ionized aqueous solution, (l):Liquid

Thermodynamic data of products

Chemical formulaStandard 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
K2SO4 (cr)-1437.79[1]-1321.37[1]175.56[1]131.46[1]
K2SO4 (g)-1096[1]-1033[1]364[1]108.8[1]
K2SO4 (ai)-1414.02[1]-1311.07[1]225.1[1]-251[1]
HBr (g)-36.40[1]-53.45[1]198.695[1]29.142[1]
HBr (ai)-121.55[1]-103.96[1]82.4[1]-141.8[1]
* (cr):Crystalline solid, (g):Gas, (ai):Ionized aqueous solution

References

List of references

  1. 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
    National Institute of Standards and Technology (NIST)