KOH (s) → K+1 (aq) + OH-1 (aq)

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Reaction Type:

Dissociation of an ionic compound in water

Enthalpy of Reaction

[1ΔHf(K+1 (aq)) + 1ΔHf(OH-1 (aq))] - [1ΔHf(KOH (s))]
[1(-252.4) + 1(-229.99)] - [1(-425.85)] = -56.54 kJ
-56.54 kJ     (exothermic)

Entropy Change

[1ΔSf(K+1 (aq)) + 1ΔSf(OH-1 (aq))] - [1ΔSf(KOH (s))]
[1(102.5) + 1(-10.75)] - [1(78.87)] = 12.88 J/K
12.88 J/K     (increase in entropy)

Free Energy of Reaction (at 298.15 K)

From ΔGf° values:
[1ΔGf(K+1 (aq)) + 1ΔGf(OH-1 (aq))] - [1ΔGf(KOH (s))]
[1(-283.3) + 1(-157.28)] - [1(-379.07)] = -61.51 kJ
-61.51 kJ     (spontaneous)

From ΔG = ΔH - TΔS:
-60.38 kJ     (spontaneous)

Equilibrium Constant, K (at 298.15 K)

59797825428.6797
This process is favorable at 25°C.

Enter an initial concentration for the ionic compound. Upon hitting submit, Ksp (59797825428.6797) will be used to calculate the equilibrium concentration for all species.

KOH K+1 OH-1
Initial M   0 0
Change -x +x +x
Equilibrium