Na2S + 2HI → 2NaI + H2S
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- Reaction of sodium sulfide and hydrogen iodide
The reaction of sodium sulfide and hydrogen iodide yields sodium iodide and hydrogen sulfide. This reaction is an acid-base reaction and is classified as follows:
Table of contents
Reaction data
Chemical equation
- Reaction of sodium sulfide and hydrogen iodide
General equation
- Salt of weak acidBrønsted base + Strong acidBrønsted acid ⟶ Salt of strong acidConjugate base + Weak acidConjugate acid
Oxidation state of each atom
- Reaction of sodium sulfide and hydrogen iodide
Reactants
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| Na2S | Sodium sulfide | 1 | Brønsted base | Salt of weak acid |
| HI | Hydrogen iodide | 2 | Brønsted acid | Strong acid |
Products
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| NaI | Sodium iodide | 2 | Conjugate base | Salt of strong acid |
| H2S | Hydrogen sulfide | 1 | Conjugate acid | Weak acid |
Thermodynamic changes
Changes in standard condition
- Reaction of sodium sulfide and hydrogen iodide◆
ΔrG −259.3 kJ/mol K 2.68 × 1045 pK −45.43
| 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 | −284.4 | −259.3 | −94.0 | – |
per 1 mol of | −284.4 | −259.3 | −94.0 | – |
per 1 mol of | −142.2 | −129.7 | −47.0 | – |
per 1 mol of | −142.2 | −129.7 | −47.0 | – |
per 1 mol of | −284.4 | −259.3 | −94.0 | – |
Changes in aqueous solution (1)
- Reaction of sodium sulfide and hydrogen iodide◆
ΔrG −119.3 kJ/mol K 7.95 × 1020 pK −20.90
| 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 | −53.6 | −119.3 | 220.5 | – |
per 1 mol of | −53.6 | −119.3 | 220.5 | – |
per 1 mol of | −26.8 | −59.65 | 110.3 | – |
per 1 mol of | −26.8 | −59.65 | 110.3 | – |
per 1 mol of | −53.6 | −119.3 | 220.5 | – |
Changes in aqueous solution (2)
- Reaction of sodium sulfide and hydrogen iodide◆
ΔrG −113.5 kJ/mol K 7.66 × 1019 pK −19.88
| 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 | −72.6 | −113.5 | 136 | – |
per 1 mol of | −72.6 | −113.5 | 136 | – |
per 1 mol of | −36.3 | −56.75 | 68.0 | – |
per 1 mol of | −36.3 | −56.75 | 68.0 | – |
per 1 mol of | −72.6 | −113.5 | 136 | – |
Thermodynamic data of reactants
| Chemical formula | Standard 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 |
|---|---|---|---|---|
| Na2S (cr) | -364.8[1] | -349.8[1] | 83.7[1] | – |
| Na2S (ai) | -447.3[1] | -438.1[1] | 103.3[1] | – |
| Na2S (cr) 4.5 hydrate | -1725.9[1] | – | – | – |
| Na2S (cr) 5 hydrate | -1886.6[1] | – | – | – |
| Na2S (cr) 9 hydrate | -3074.0[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, (ai):Ionized aqueous solution, (g):Gas
Thermodynamic data of products
| Chemical formula | Standard 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 |
|---|---|---|---|---|
| NaI (cr) | -287.78[1] | -286.06[1] | 98.53[1] | 52.09[1] |
| NaI (g) | -79.5[1] | -121.0[1] | 248.978[1] | 36.65[1] |
| NaI (ai) | -295.31[1] | -313.47[1] | 170.3[1] | -95.8[1] |
| NaI (cr) 1 hydrate | -883.096[1] | -771.10[1] | 196.2[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
- 1Janiel J. Reed (1989)The NBS Tables of Chemical Thermodynamic Properties: Selected Values for Inorganic and C1 and C2 Organic Substances in SI UnitsNational Institute of Standards and Technology (NIST)
- ^ ΔfH°, -364.8 kJ · mol−1
- ^ ΔfG°, -349.8 kJ · mol−1
- ^ S°, 83.7 J · K−1 · mol−1
- ^ ΔfH°, -447.3 kJ · mol−1
- ^ ΔfG°, -438.1 kJ · mol−1
- ^ S°, 103.3 J · K−1 · mol−1
- ^ ΔfH°, -1725.9 kJ · mol−1
- ^ ΔfH°, -1886.6 kJ · mol−1
- ^ ΔfH°, -3074.0 kJ · mol−1
- ^ ΔfH°, 26.48 kJ · mol−1
- ^ ΔfG°, 1.70 kJ · mol−1
- ^ S°, 206.594 J · K−1 · mol−1
- ^ Cp°, 29.158 J · K−1 · mol−1
- ^ ΔfH°, -55.19 kJ · mol−1
- ^ ΔfG°, -51.57 kJ · mol−1
- ^ S°, 111.3 J · K−1 · mol−1
- ^ Cp°, -142.3 J · K−1 · mol−1
- ^ ΔfH°, -287.78 kJ · mol−1
- ^ ΔfG°, -286.06 kJ · mol−1
- ^ S°, 98.53 J · K−1 · mol−1
- ^ Cp°, 52.09 J · K−1 · mol−1
- ^ ΔfH°, -79.5 kJ · mol−1
- ^ ΔfG°, -121.0 kJ · mol−1
- ^ S°, 248.978 J · K−1 · mol−1
- ^ Cp°, 36.65 J · K−1 · mol−1
- ^ ΔfH°, -295.31 kJ · mol−1
- ^ ΔfG°, -313.47 kJ · mol−1
- ^ S°, 170.3 J · K−1 · mol−1
- ^ Cp°, -95.8 J · K−1 · mol−1
- ^ ΔfH°, -883.096 kJ · mol−1
- ^ ΔfG°, -771.10 kJ · mol−1
- ^ S°, 196.2 J · K−1 · mol−1
- ^ ΔfH°, -20.63 kJ · mol−1
- ^ ΔfG°, -33.56 kJ · mol−1
- ^ S°, 205.79 J · K−1 · mol−1
- ^ Cp°, 34.23 J · K−1 · mol−1
- ^ ΔfH°, -39.7 kJ · mol−1
- ^ ΔfG°, -27.83 kJ · mol−1
- ^ S°, 121. J · K−1 · mol−1