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MgS + 2HI → MgI2 + H2S

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Reaction of magnesium sulfide and hydrogen iodide
MgSMagnesium sulfide + 2HIHydrogen iodide
⟶
MgI2Magnesium iodide + H2SHydrogen sulfide

The reaction of magnesium sulfide and hydrogen iodide yields magnesium iodide and hydrogen sulfide. This reaction is an acid-base reaction and is classified as follows:

Table of contents
  1. 1Reaction data
  2. 2Thermodynamic changes
  3. 3References
  4. 4Related categories

Reaction data

Chemical equation

Reaction of magnesium sulfide and hydrogen iodide
MgSMagnesium sulfide + 2HIHydrogen iodide
⟶
MgI2Magnesium iodide + H2SHydrogen sulfide

General equation

Reaction of salt of weak acid and strong acid with generating weak acid
Salt of weak acidBrønsted base + Strong acidBrønsted acid
⟶
Salt of strong acidConjugate base + Weak acidConjugate acid

Oxidation state of each atom

Reaction of magnesium sulfide and hydrogen iodide

Reactants

Chemical formulaNameCoefficientTypeType in general
equation
MgSMagnesium sulfide1
Brønsted base
Salt of weak acid
HIHydrogen iodide2
Brønsted acid
Strong acid

Products

Chemical formulaNameCoefficientTypeType in general
equation
MgI2Magnesium iodide1
Conjugate base
Salt of strong acid
H2SHydrogen sulfide1
Conjugate acid
Weak acid

Thermodynamic changes

Changes in standard condition

Reaction of magnesium sulfide and hydrogen iodide
◆
ΔrG−53.4 kJ/mol
K2.27 × 109
pK−9.36
MgSCrystalline solid + 2HIGas
⟶
MgI2Crystalline solid + H2SGas
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
−91.6−53.4−128.0–
per 1 mol of
−91.6−53.4−128.0–
per 1 mol of
−45.8−26.7−64.00–
per 1 mol of
−91.6−53.4−128.0–
per 1 mol of
−91.6−53.4−128.0–

Changes in aqueous solution (1)

Reaction of magnesium sulfide and hydrogen iodide
◆
ΔrG−146.7 kJ/mol
K5.02 × 1025
pK−25.70
MgSCrystalline solid + 2HIIonized aqueous solution
⟶
MgI2Ionized aqueous solution + H2SGas
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
−141.5−146.717.4–
per 1 mol of
−141.5−146.717.4–
per 1 mol of
−70.75−73.358.70–
per 1 mol of
−141.5−146.717.4–
per 1 mol of
−141.5−146.717.4–

Changes in aqueous solution (2)

Reaction of magnesium sulfide and hydrogen iodide
◆
ΔrG−141.0 kJ/mol
K5.04 × 1024
pK−24.70
MgSCrystalline solid + 2HIIonized aqueous solution
⟶
MgI2Ionized aqueous solution + H2SUn-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
−160.5−141.0−67–
per 1 mol of
−160.5−141.0−67–
per 1 mol of
−80.25−70.50−34–
per 1 mol of
−160.5−141.0−67–
per 1 mol of
−160.5−141.0−67–

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
MgS (cr)-346.0[1]-341.8[1]50.33[1]45.56[1]
HI (g)26.48[1]1.70[1]206.594[1]29.158[1]
HI (ai)-55.19[1]-51.57[1]111.3[1]-142.3[1]
* (cr):Crystalline solid, (g):Gas, (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
MgI2 (cr)-364.0[1]-358.2[1]129.7[1]–
MgI2 (g)-172[1]–––
MgI2 (ai)-577.22[1]-558.1[1]84.5[1]–
H2S (g)-20.63[1]-33.56[1]205.79[1]34.23[1]
H2S (ao)-39.7[1]-27.83[1]121[1]–
* (cr):Crystalline solid, (g):Gas, (ai):Ionized aqueous solution, (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)