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3I2 + 6KOH → KIO3 + 5KI + 3H2O

The reaction of iodine and potassium hydroxide yields potassium iodate, potassium iodide, and water. 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 categories

Reaction data

Chemical equation

General equation

Reaction of self redoxing species and base
Self-redoxing speciesSelf redox agent + BaseNon-redox agent
ProductOxidation product + ProductReduction product
Reaction of nonmetal and hydroxide base
NonmetalSelf redox agent + Hydroxide base
Oxoacid saltOxidation product + Salt of hydracid/HydrideReduction product + OxideNon-redox product

Oxidation state of each atom

Reaction of iodine and potassium hydroxide

Reactants

Chemical formulaNameCoefficientTypeType in general
equation
I2Iodine3
Self redoxing
Nonmetal
KOHPotassium hydroxide6
Base
Hydroxide base

Products

Chemical formulaNameCoefficientTypeType in general
equation
KIO3Potassium iodate1
Oxidized
Oxoacid salt
KIPotassium iodide5
Reduced
Salt of hydracid
H2OWater3
Hydride

Thermodynamic changes

Changes in standard condition

Reaction of iodine and potassium hydroxide
ΔrG−479.72 kJ/mol
K1.10 × 1084
pK−84.04
3I2Crystalline solid + 6KOHCrystalline solid
KIO3Crystalline solid + 5KICrystalline solid + 3H2OLiquid
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
−449.78−479.7271.044.3
per 1 mol of
−149.93−159.9123.714.8
−74.963−79.95311.87.38
per 1 mol of
−449.78−479.7271.044.3
per 1 mol of
−89.956−95.94414.28.86
per 1 mol of
−149.93−159.9123.714.8

Changes in aqueous solution

Reaction of iodine and potassium hydroxide
ΔrG−203.0 kJ/mol
K3.66 × 1035
pK−35.56
3I2Un-ionized aqueous solution + 6KOHIonized aqueous solution
KIO3Ionized aqueous solution + 5KIIonized aqueous solution + 3H2OLiquid
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
−42.5−203.0538.4
per 1 mol of
−14.2−67.67179.5
−7.08−33.8389.73
per 1 mol of
−42.5−203.0538.4
per 1 mol of
−8.50−40.60107.7
per 1 mol of
−14.2−67.67179.5

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
I2 (cr)0[1]0[1]116.135[1]54.438[1]
I2 (g)62.438[1]19.327[1]260.69[1]36.90[1]
I2 (ao)22.6[1]16.40[1]137.2[1]
KOH (cr)-424.764[1]-379.08[1]78.9[1]64.9[1]
KOH (g)-231.0[1]-232.6[1]238.3[1]49.20[1]
KOH (ai)-482.37[1]-440.50[1]91.6[1]-126.8[1]
KOH (cr)
1 hydrate
-748.9[1]-645.1[1]117.2[1]
KOH (cr)
2 hydrate
-1051.0[1]-887.3[1]150.6[1]
* (cr):Crystalline solid, (g):Gas, (ao):Un-ionized aqueous solution, (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
KIO3 (cr)-501.37[1]-418.35[1]151.46[1]106.48[1]
KIO3 (ai)-473.6[1]-411.2[1]220.9[1]
KI (cr)-327.900[1]-324.892[1]106.32[1]52.93[1]
KI (g)-125.5[1]-166.1[1]258.3[1]37.11[1]
KI (ai)-307.57[1]-334.85[1]213.8[1]-120.5[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, (g):Gas, (l):Liquid

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)