Le Chatelier's Principle and Solubility

The video tutorial explains how changing the pH of a solution can affect the solubility of slightly soluble salts, using lead II fluoride as an example. It describes how adding H+ ions decreases the pH, causing a shift in equilibrium that increases solubility. The tutorial also covers the role of basic anions like fluoride, hydroxide, and carbonate in solubility changes. It contrasts this with lead II chloride, where the chloride anion's negligible basicity means pH changes do not affect solubility.

What happens to the solubility of a slightly soluble salt when the pH of the solution is decreased?

• It becomes zero.

• It decreases.

• It increases.

• It remains unchanged.

When H+ ions are added to a solution of lead(II) fluoride, what happens to the fluoride ions?

• They increase in concentration.

• They remain unchanged.

• They precipitate out of solution.

• They react to form HF.

According to Le Chatelier's principle, how does the system respond to a decrease in fluoride ion concentration?

• Remains at equilibrium.

• Forms a new compound.

• Shifts to the left to form more solid.

• Shifts to the right to dissolve more solid.

Which of the following anions is considered a basic anion?

• Chloride

• Fluoride

• Nitrate

• Sulfate

What is the effect of adding H+ ions to a solution containing a compound with hydroxide ions?

• Decreases solubility

• Increases solubility

• Forms a precipitate

• No effect

What remains constant for lead(II) fluoride when the pH is decreased at a constant temperature?

• Molar solubility

• Ksp value

• Concentration of Pb2+ ions

• Concentration of F- ions

How does the solubility of lead(II) chloride change when the pH is decreased?

• It increases.

• It remains unchanged.

• It decreases.

• It becomes zero.

Why does the solubility of lead(II) chloride remain unchanged when pH is decreased?

• Lead ions precipitate out.

• Chloride ions are anions of negligible basicity.

• Chloride ions react with H+ ions.

• The solution becomes saturated.

What is an anion of negligible basicity?

• An anion that reacts strongly with H+ ions.

• An anion that does not react with H+ ions.

• An anion that forms a precipitate.

• An anion that increases solubility.

Which of the following salts is unaffected by changes in pH due to its anion's negligible basicity?

• Calcium carbonate

• Sodium hydroxide

• Lead(II) fluoride

• Lead(II) chloride