Four ionic compounds are tested for their ability to dissolve in water at 25 °C

CHEMISTRY · Multi-part · AP · Chemistry · Equilibrium · Equilibrium

Problem

Four ionic compounds are tested for their ability to dissolve in water at 25 °C. The experimentally determined KspK_{sp} values are provided.
CompoundFormulaKspK_{sp}
Potassium acetateKC2H3O2\mathrm{KC_{2}H_{3}O_{2}}3.7
Silver bromideAgBr\mathrm{AgBr}5.0×10−135.0\times10^{-13}
Magnesium hydroxideMg(OH)2\mathrm{Mg(OH)_{2}}5.6×10−125.6\times10^{-12}
Assume ideal behavior and disregard any acid–base reactions that acetate or hydroxide ions might undergo. (a) Identify which compound will dissolve to completion when a small sample is added to water and justify your answer using the numerical data in the table. (b) For each of the two sparingly soluble compounds, write the algebraic relationship between KspK_{sp} and molar solubility ss, then calculate ss at 25 °C. (c) Determine by what factor the more soluble of the two sparingly soluble salts exceeds the less soluble one in molar solubility, and discuss whether this factor is large enough to be significant in a qualitative laboratory test based on precipitation.

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