Which of the slightly soluble salts below will be more soluble in acidic solution than in pure water?

a. Mg (OH) 2

b. CaCO3

c. AgCl Mg (OH) 2

d. only Mg (OH) 2,

e. CaCO3, and

f. AgCl

g. CaCO3 only

h. both Mg (OH) 2 and CaCO3

h. both Mg (OH) ₂ and CaCO₃

Explanation:

Let's consider the solution of Mg (OH) ₂ according to the following equation:

Mg (OH) ₂ (s) ⇄ Mg²⁺ (aq) + 2 OH⁻ (aq)

In acidic solution, OH⁻ reacts with H⁺ to form H₂O.

OH⁻ (aq) + H⁺ (aq) ⇄ H₂O (l)

According to Le Chatelier's principle, since [OH⁻] decreases, the solution of Mg (OH) ₂ (s) shifts toward the right, increasing its solubility.

Let's consider the solution of CaCO₃ according to the following equation:

CaCO₃ (s) ⇄ Ca²⁺ (aq) + CO₃²⁻ (aq)

In acidic solution, CO₃²⁻ reacts with H⁺ to form HCO₃⁻.

CO₃²⁻ (aq) + H⁺ (aq) ⇄ HCO₃⁻ (aq)

According to Le Chatelier's principle, since [CO₃²⁻] decreases, the solution of CaCO₃ (s) shifts toward the right, increasing its solubility.

Let's consider the solution of AgCl according to the following equation:

AgCl (s) ⇄ Ag⁺ (aq) + Cl⁻ (aq)

Cl⁻ does not react with H⁺ because it comes from a strong acid (HCl). Therefore, the solubility of AgCl (s) is not affected by the pH.