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2K + H2SO4 → K2SO3 + H2O

The reaction of potassium and sulfuric acid yields potassium sulfite and water (Other reactions are here). This reaction is an oxidation-reduction 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

Reaction of reducing species and reducible species
Reducing speciesReducing agent + Reducible speciesOxidizing agent
ProductOxidation product + ProductReduction product

Oxidation state of each atom

Reaction of potassium and sulfuric acid

Reactants

Chemical formulaNameCoefficientTypeType in general
equation
KPotassium2
Reducing
Reducing
H2SO4Sulfuric acid1
Oxidizing
Reducible

Products

Chemical formulaNameCoefficientTypeType in general
equation
K2SO3Potassium sulfite1
Redoxed product
H2OWater1

Thermodynamic changes

Changes in standard condition

Reaction of potassium and sulfuric acid
2KCrystalline solid + H2SO4Liquid
K2SO3Crystalline solid + H2OLiquid
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
−597.3
per 1 mol of
−298.6
per 1 mol of
−597.3
per 1 mol of
−597.3
per 1 mol of
−597.3

Changes in aqueous solution

Reaction of potassium and sulfuric acid
ΔrG−545.7 kJ/mol
K4.00 × 1095
pK−95.60
2KCrystalline solid + H2SO4Ionized aqueous solution
K2SO3Ionized aqueous solution + H2OLiquid
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
−516.7−545.797
per 1 mol of
−258.4−272.949
per 1 mol of
−516.7−545.797
per 1 mol of
−516.7−545.797
per 1 mol of
−516.7−545.797

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
K (cr)0[1]0[1]64.18[1]29.58[1]
K (g)89.24[1]60.59[1]160.336[1]20.786[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, (l):Liquid, (ai):Ionized aqueous solution

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
K2SO3 (cr)-1125.5[1]
K2SO3 (ai)-1140.1[1]-1053.1[1]176[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. 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)