NaI (s) → Na+1 (aq) + I-1 (aq)

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Reaction Type:

Dissociation of an ionic compound in water

Enthalpy of Reaction

[1ΔHf(Na+1 (aq)) + 1ΔHf(I-1 (aq))] - [1ΔHf(NaI (s))]
[1(-240.1) + 1(-55.19)] - [1(-288.03)] = -7.25999999999999 kJ
-7.26 kJ     (exothermic)

Entropy Change

[1ΔSf(Na+1 (aq)) + 1ΔSf(I-1 (aq))] - [1ΔSf(NaI (s))]
[1(59) + 1(111.29)] - [1(98.32)] = 71.97 J/K
71.97 J/K     (increase in entropy)

Free Energy of Reaction (at 298.15 K)

From ΔGf° values:
[1ΔGf(Na+1 (aq)) + 1ΔGf(I-1 (aq))] - [1ΔGf(NaI (s))]
[1(-261.9) + 1(-51.59)] - [1(-284.51)] = -28.98 kJ
-28.98 kJ     (spontaneous)

From ΔG = ΔH - TΔS:
-28.72 kJ     (spontaneous)

Equilibrium Constant, K (at 298.15 K)

119497.50734
This process is favorable at 25°C.

Enter an initial concentration for the ionic compound. Upon hitting submit, Ksp (119497.50734) will be used to calculate the equilibrium concentration for all species.

NaI Na+1 I-1
Initial M   0 0
Change -x +x +x
Equilibrium