Chemistry Forum

From the following thermodynamic data (at 25℃), compute the free energy of solution for silver fluoride and silver chloride at 25℃.

On the basis of your answers, comment on the relative solubilities of two compounds:
For AgF : Lattice energy = 967 kJ/mol
Heat of hydration = 987 kJ/mol
Entropy of solution = -19.8 kJ/mol-K

For AgCl: Lattice energy = 918 kJ/mol
Heat of hydration = 852 kJ/mol
Entropy of solution = + 31.5 kJ/mol-K

I am working on this question. Any chemistry help will be accepted.

Your ideas please?

AgF solubility:
\(AgF(s) \rightarrow Ag^+(g) + F^-(g) \Delta {H} = 967kJ/mol\)

\( Ag^+(g) + F^- (g) \rightarrow Ag^+ (aq) + F^- (aq) \Delta{H} = 987 kJ/mol \)
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\(AgF(s) \rightarrow Ag^+ (aq) + F^-{aq} \Delta{H}_{solution}= -20 kJ/mol \)

\( \Delta {G} = \Delta {H} - T\Delta {S}\)

\( \Delta G= -20 kJ/mol -298 K (-0.0198 kJ /{mol-K} )\)

\( \Delta G = -14.1 kJ/mol\) Because \( \Delta G < 0 \) reaction is spontaneous that is AgF should dissolve.

AgCl solubility:

\( AgCl(s) \rightarrow Ag^+ (g) + Cl^-(g) \Delta H= 918 kJ/mol \)

\( Ag^+(g) + Cl^-(g) \rightarrow Ag^+(aq) + Cl^- (aq) \Delta H = 852 kJ/mol\)
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\( AgCl(s) \rightarrow Ag^+ (aq) + Cl^- (aq) \Delta H_{solution} =66 kJ/mol\)

\( \Delta G = \Delta H - T \Delta S\)

\( \Delta G = 66 kJ /mol - 298 K( 0.0317 kJ /{mol-K})\)

\( \Delta G = 56.5 kJ /mol \)
Because \( \Delta G > 0 \) reaction is non-spontaneous that means AgCl should not disolve.