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2HCN ⚡→ N2↑ + 2C + H2↑

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Electrolysis of hydrogen cyanide
2HCNHydrogen cyanide
⚡
⟶
N2↑Nitrogen + 2CCarbon + H2↑Hydrogen

Electrolysis of hydrogen cyanide yields nitrogen, carbon, and hydrogen (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

Electrolysis of hydrogen cyanide
2HCNHydrogen cyanide
⚡
⟶
N2↑Nitrogen + 2CCarbon + H2↑Hydrogen

General equation

Electrolysis of liquid substance
LiquidSelf redox agent
⚡
⟶
ProductOxidation product + ProductReduction product

Oxidation state of each atom

Electrolysis of hydrogen cyanide

Reactants

Chemical formulaNameCoefficientTypeType in general
equation
HCNHydrogen cyanide2
Self redox agent
Liquid

Products

Chemical formulaNameCoefficientTypeType in general
equation
N2Nitrogen1
Oxidized
–
CCarbon2
Reduced
–
H2Hydrogen1
Reduced
–

Thermodynamic changes

Changes in standard condition (1)

Electrolysis of hydrogen cyanide
◆
ΔrG−249.94 kJ/mol
K6.13 × 1043
pK−43.79
2HCNLiquid
⚡
⟶
N2↑Gas + 2CCrystalline solidgraphite + H2↑Gas
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
−217.74−249.94108.09−66.26
per 1 mol of
−108.87−124.9754.045−33.13
per 1 mol of
−217.74−249.94108.09−66.26
per 1 mol of
−108.87−124.9754.045−33.13
per 1 mol of
−217.74−249.94108.09−66.26

Changes in standard condition (2)

Electrolysis of hydrogen cyanide
◆
ΔrG−244.14 kJ/mol
K5.91 × 1042
pK−42.77
2HCNLiquid
⚡
⟶
N2↑Gas + 2CCrystalline soliddiamond + H2↑Gas
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
−213.95−244.14101.37−71.09
per 1 mol of
−106.97−122.0750.685−35.55
per 1 mol of
−213.95−244.14101.37−71.09
per 1 mol of
−106.97−122.0750.685−35.55
per 1 mol of
−213.95−244.14101.37−71.09

Changes in aqueous solution (1)

Electrolysis of hydrogen cyanide
◆
ΔrG−344.8 kJ/mol
K2.55 × 1060
pK−60.41
2HCNIonized aqueous solution
⚡
⟶
N2↑Gas + 2CCrystalline solidgraphite + H2↑Gas
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
−301.2−344.8145.6–
per 1 mol of
−150.6−172.472.80–
per 1 mol of
−301.2−344.8145.6–
per 1 mol of
−150.6−172.472.80–
per 1 mol of
−301.2−344.8145.6–

Changes in aqueous solution (2)

Electrolysis of hydrogen cyanide
◆
ΔrG−327.2 kJ/mol
K2.10 × 1057
pK−57.32
2HCNIonized aqueous solution
⚡
⟶
N2↑Gas + 2CCrystalline solidgraphite + H2↑Un-ionized 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
−305.4−327.2592–
per 1 mol of
−152.7−163.6296–
per 1 mol of
−305.4−327.2592–
per 1 mol of
−152.7−163.6296–
per 1 mol of
−305.4−327.2592–

Changes in aqueous solution (3)

Electrolysis of hydrogen cyanide
◆
ΔrG−239.4 kJ/mol
K8.73 × 1041
pK−41.94
2HCNUn-ionized aqueous solution
⚡
⟶
N2↑Gas + 2CCrystalline solidgraphite + H2↑Gas
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
−214.2−239.484.4–
per 1 mol of
−107.1−119.742.2–
per 1 mol of
−214.2−239.484.4–
per 1 mol of
−107.1−119.742.2–
per 1 mol of
−214.2−239.484.4–

Changes in aqueous solution (4)

Electrolysis of hydrogen cyanide
◆
ΔrG−221.8 kJ/mol
K7.21 × 1038
pK−38.86
2HCNUn-ionized aqueous solution
⚡
⟶
N2↑Gas + 2CCrystalline solidgraphite + H2↑Un-ionized 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
−218.4−221.8531–
per 1 mol of
−109.2−110.9266–
per 1 mol of
−218.4−221.8531–
per 1 mol of
−109.2−110.9266–
per 1 mol of
−218.4−221.8531–

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
HCN (l)108.87[1]124.97[1]112.84[1]70.63[1]
HCN (g)135.1[1]124.7[1]201.78[1]35.86[1]
HCN (ai)150.6[1]172.4[1]94.1[1]–
HCN (ao)107.1[1]119.7[1]124.7[1]–
* (l):Liquid, (g):Gas, (ai):Ionized aqueous solution, (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
N2 (g)0[1]0[1]191.61[1]29.125[1]
C (cr)
graphite
0[1]0[1]5.740[1]8.527[1]
C (cr)
diamond
1.895[1]2.900[1]2.377[1]6.113[1]
C (g)716.682[1]671.257[1]158.096[1]20.838[1]
H2 (g)0[1]0[1]130.684[1]28.824[1]
H2 (ao)-4.2[1]17.6[1]577[1]–
* (g):Gas, (cr):Crystalline solid, (ao):Un-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)