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2HPO42− + 2e− → 2PO43− + H2

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Reduction of hydrogenphosphate ion
2HPO42−Hydrogenphosphate ion + 2e−Electron
⟶
2PO43−Phosphate ion + H2Hydrogen

Reduction of hydrogenphosphate ion yields phosphate ion 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

Reduction of hydrogenphosphate ion
2HPO42−Hydrogenphosphate ion + 2e−Electron
⟶
2PO43−Phosphate ion + H2Hydrogen

General equation

Reduction of reducible species
ReactantOxidizing agent + e−
⟶
ProductReduction product

Oxidation state of each atom

Reduction of hydrogenphosphate ion

Reactants

Chemical formulaNameCoefficientTypeType in general
equation
HPO42−Hydrogenphosphate ion2
Oxidizing
–
e−Electron2
–
Electron

Products

Chemical formulaNameCoefficientTypeType in general
equation
PO43−Phosphate ion2
–
–
H2Hydrogen1
Reduced
–

Thermodynamic changes

Changes in standard condition (1)

Reduction of hydrogenphosphate ion
◆
ΔrG140.9 kJ/mol
K0.21 × 10−24
pK24.68
2HPO42−Un-ionized aqueous solution + 2e−
⟶
2PO43−Un-ionized aqueous solution + H2Gas
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
29.5140.9−242.9–
per 1 mol of
Hydrogenphosphate ion
14.870.45−121.5–
per 1 mol of
Electron
14.870.45−121.5–
per 1 mol of
Phosphate ion
14.870.45−121.5–
per 1 mol of
29.5140.9−242.9–

Changes in standard condition (2)

Reduction of hydrogenphosphate ion
◆
ΔrG158.5 kJ/mol
K0.17 × 10−27
pK27.77
2HPO42−Un-ionized aqueous solution + 2e−
⟶
2PO43−Un-ionized aqueous solution + H2Un-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
25.3158.5203–
per 1 mol of
Hydrogenphosphate ion
12.779.25102–
per 1 mol of
Electron
12.779.25102–
per 1 mol of
Phosphate ion
12.779.25102–
per 1 mol of
25.3158.5203–

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
HPO42− (ao)-1292.14[1]-1089.15[1]-33.5[1]–
e−––––
* (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
PO43− (ao)-1277.4[1]-1018.7[1]-220.3[1]–
H2 (g)0[1]0[1]130.684[1]28.824[1]
H2 (ao)-4.2[1]17.6[1]577[1]–
* (ao):Un-ionized aqueous solution, (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)