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4KClO + 4HNO2 → 4KNO2 + 2Cl2↑ + O2↑ + 2H2O

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Reaction of potassium hypochlorite and nitrous acid
4KClOPotassium hypochlorite + 4HNO2Nitrous acid
⟶
4KNO2Potassium nitrite + 2Cl2↑Chlorine + O2↑Oxygen + 2H2OWater

The reaction of potassium hypochlorite and nitrous acid yields potassium nitrite, chlorine, oxygen, 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

Reaction of potassium hypochlorite and nitrous acid
4KClOPotassium hypochlorite + 4HNO2Nitrous acid
⟶
4KNO2Potassium nitrite + 2Cl2↑Chlorine + O2↑Oxygen + 2H2OWater

General equation

Reaction of self redoxing species and acid
Self-redoxing speciesSelf redox agent + AcidNon-redox agent
⟶
ProductOxidation product + ProductReduction product

Oxidation state of each atom

Reaction of potassium hypochlorite and nitrous acid

Reactants

Chemical formulaNameCoefficientTypeType in general
equation
KClOPotassium hypochlorite4
Oxidizing
Self redoxing
HNO2Nitrous acid4
–
Acid

Products

Chemical formulaNameCoefficientTypeType in general
equation
KNO2Potassium nitrite4
–
–
Cl2Chlorine2
Reduced
–
O2Oxygen1
–
–
H2OWater2
–
–

Thermodynamic changes

Changes in aqueous solution (1)

Reaction of potassium hypochlorite and nitrous acid
◆
ΔrG−253.5 kJ/mol
K2.58 × 1044
pK−44.41
4KClOIonized aqueous solution + 4HNO2Un-ionized aqueous solution
⟶
4KNO2Ionized aqueous solution + 2Cl2↑Gas + O2↑Gas + 2H2OLiquid
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
−84.9−253.5567–
−21.2−63.38142–
per 1 mol of
−21.2−63.38142–
per 1 mol of
−21.2−63.38142–
per 1 mol of
−42.5−126.8284–
per 1 mol of
−84.9−253.5567–
per 1 mol of
−42.5−126.8284–

Changes in aqueous solution (2)

Reaction of potassium hypochlorite and nitrous acid
◆
ΔrG−237.1 kJ/mol
K3.45 × 1041
pK−41.54
4KClOIonized aqueous solution + 4HNO2Un-ionized aqueous solution
⟶
4KNO2Ionized aqueous solution + 2Cl2↑Gas + O2↑Un-ionized aqueous solution + 2H2OLiquid
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
−96.6−237.1472–
−24.1−59.27118–
per 1 mol of
−24.1−59.27118–
per 1 mol of
−24.1−59.27118–
per 1 mol of
−48.3−118.5236–
per 1 mol of
−96.6−237.1472–
per 1 mol of
−48.3−118.5236–

Changes in aqueous solution (3)

Reaction of potassium hypochlorite and nitrous acid
◆
ΔrG−239.6 kJ/mol
K9.46 × 1041
pK−41.98
4KClOIonized aqueous solution + 4HNO2Un-ionized aqueous solution
⟶
4KNO2Ionized aqueous solution + 2Cl2↑Un-ionized aqueous solution + O2↑Gas + 2H2OLiquid
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
−131.7−239.6363–
−32.92−59.9090.8–
per 1 mol of
−32.92−59.9090.8–
per 1 mol of
−32.92−59.9090.8–
per 1 mol of
−65.85−119.8182–
per 1 mol of
−131.7−239.6363–
per 1 mol of
−65.85−119.8182–

Changes in aqueous solution (4)

Reaction of potassium hypochlorite and nitrous acid
◆
ΔrG−223.2 kJ/mol
K1.27 × 1039
pK−39.10
4KClOIonized aqueous solution + 4HNO2Un-ionized aqueous solution
⟶
4KNO2Ionized aqueous solution + 2Cl2↑Un-ionized aqueous solution + O2↑Un-ionized aqueous solution + 2H2OLiquid
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
−143.4−223.2268–
−35.85−55.8067.0–
per 1 mol of
−35.85−55.8067.0–
per 1 mol of
−35.85−55.8067.0–
per 1 mol of
−71.70−111.6134–
per 1 mol of
−143.4−223.2268–
per 1 mol of
−71.70−111.6134–

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
KClO (ai)-359.4[1]-320.0[1]146[1]–
HNO2 (g)
cis
-77.99[1]-42.94[1]248.76[1]44.77[1]
HNO2 (g)
trans
-80.12[1]-45.24[1]249.22[1]46.07[1]
HNO2 (g)-79.5[1]-46.0[1]254.1[1]45.6[1]
HNO2 (ao)-119.2[1]-50.6[1]135.6[1]–
* (ai):Ionized aqueous solution, (g):Gas, (ao):Un-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
KNO2 (cr)
rhombic
-369.82[1]-306.55[1]152.09[1]107.40[1]
KNO2 (ai)-356.9[1]-315.4[1]225.5[1]–
Cl2 (g)0[1]0[1]223.066[1]33.907[1]
Cl2 (ao)-23.4[1]6.94[1]121[1]–
O2 (g)0[1]0[1]205.138[1]29.355[1]
O2 (ao)-11.7[1]16.4[1]110.9[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, (ao):Un-ionized aqueous solution, (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)