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2HNO2 + Cl2 → 2NO2 + 2HCl

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Reaction of nitrous acid and chlorine
2HNO2Nitrous acid + Cl2Chlorine
⟶
2NO2Nitrogen dioxide + 2HClHydrogen chloride

The reaction of nitrous acid and chlorine yields nitrogen dioxide and hydrogen chloride (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 nitrous acid and chlorine
2HNO2Nitrous acid + Cl2Chlorine
⟶
2NO2Nitrogen dioxide + 2HClHydrogen chloride

General equation

Reaction of oxidizable species and oxidizing species
Oxidizable speciesReducing agent + Oxidizing speciesOxidizing agent
⟶
ProductOxidation product + ProductReduction product

Oxidation state of each atom

Reaction of nitrous acid and chlorine

Reactants

Chemical formulaNameCoefficientTypeType in general
equation
HNO2Nitrous acid2
Reducing
Oxidizable
Cl2Chlorine1
Oxidizing
Oxidizing

Products

Chemical formulaNameCoefficientTypeType in general
equation
NO2Nitrogen dioxide2
Oxidized
–
HClHydrogen chloride2
Reduced
–

Thermodynamic changes

Changes in standard condition (1)

Reaction of nitrous acid and chlorine
◆
ΔrG6.3 kJ/mol
K0.79 × 10−1
pK1.10
2HNO2Un-ionized aqueous solution + Cl2Un-ionized aqueous solution
⟶
2NO2Gas + 2HClGas
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
143.56.3462–
per 1 mol of
71.753.1231–
per 1 mol of
143.56.3462–
per 1 mol of
71.753.1231–
per 1 mol of
71.753.1231–

Changes in standard condition (2)

Reaction of nitrous acid and chlorine
◆
ΔrG−65.6 kJ/mol
K3.11 × 1011
pK−11.49
2HNO2Un-ionized aqueous solution + Cl2Un-ionized aqueous solution
⟶
2NO2Gas + 2HClIonized 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
−6.2−65.6201–
per 1 mol of
−3.1−32.8101–
per 1 mol of
−6.2−65.6201–
per 1 mol of
−3.1−32.8101–
per 1 mol of
−3.1−32.8101–

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
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]–
Cl2 (g)0[1]0[1]223.066[1]33.907[1]
Cl2 (ao)-23.4[1]6.94[1]121[1]–
* (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
NO2 (g)33.18[1]51.31[1]240.06[1]37.20[1]
HCl (g)-92.307[1]-95.299[1]186.908[1]29.12[1]
HCl (ai)-167.159[1]-131.228[1]56.5[1]-136.4[1]
* (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)