KI (s) → K+1 (aq) + I-1 (aq)

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Reaction Type:

Dissociation of an ionic compound in water

Enthalpy of Reaction

[1ΔHf(K+1 (aq)) + 1ΔHf(I-1 (aq))] - [1ΔHf(KI (s))]
[1(-252.4) + 1(-55.19)] - [1(-327.65)] = 20.0599999999999 kJ
20.06 kJ     (endothermic)

Entropy Change

[1ΔSf(K+1 (aq)) + 1ΔSf(I-1 (aq))] - [1ΔSf(KI (s))]
[1(102.5) + 1(111.29)] - [1(106.4)] = 107.39 J/K
107.39 J/K     (increase in entropy)

Free Energy of Reaction (at 298.15 K)

From ΔGf° values:
[1ΔGf(K+1 (aq)) + 1ΔGf(I-1 (aq))] - [1ΔGf(KI (s))]
[1(-283.3) + 1(-51.59)] - [1(-322.29)] = -12.6 kJ
-12.60 kJ     (spontaneous)

From ΔG = ΔH - TΔS:
-11.96 kJ     (spontaneous)

Equilibrium Constant, K (at 298.15 K)

161.26767488
This process is favorable at 25°C.

Enter an initial concentration for the ionic compound. Upon hitting submit, Ksp (161.26767488) will be used to calculate the equilibrium concentration for all species.

KI K+1 I-1
Initial M   0 0
Change -x +x +x
Equilibrium