Preparation of salts：练习题

Based on the general solubility rules for salts, which of the following groups contains only salts that are all soluble in water?

Which pair of aqueous solutions, when mixed together, will produce a precipitate of calcium sulfate, \(CaSO_4\)?

To prepare a pure sample of the insoluble salt lead(II) chloride, \(PbCl_2\), which pair of aqueous solutions should be mixed together?

According to the general solubility rules, which of the following salts is insoluble in water?

Which of the following best defines a hydrated substance in the context of salt preparation?

Based on the general solubility rules for salts, state whether magnesium nitrate, \(Mg(NO_3)_2\), is soluble or insoluble in water.

Explain why excess copper(II) oxide is used when reacting it with dilute sulfuric acid to prepare a pure sample of copper(II) sulfate crystals.

Write the ionic equation, including state symbols, for the preparation of the insoluble salt lead(II) chloride (\(PbCl_2\)) from aqueous ions.

A student wants to prepare a pure, dry sample of the soluble salt magnesium sulfate by reacting an insoluble base with a suitable dilute acid.

(a) Name the insoluble base and the dilute acid the student should use for this preparation.
(b) Describe the experimental procedure to ensure that all the acid has reacted.
(c) After the reaction is complete, the mixture is filtered. Explain why filtration is necessary at this stage.
(d) Briefly outline how the student can obtain large, pure crystals of magnesium sulfate from the resulting filtrate.

Barium sulfate ( $$ \text{BaSO}_4 $$ ) is an insoluble salt used in medical imaging. The general solubility rules indicate that sulfates are soluble, except for barium, calcium, and lead sulfates.

(a) State the names and formulae of two soluble compounds that could be reacted together to prepare barium sulfate by the precipitation method.

(b) Describe the method used to prepare a pure, dry sample of barium sulfate starting from the two aqueous solutions named in part (a).

(c) Write the full balanced symbol equation for the reaction, including state symbols.

(d) Write the ionic equation for the precipitation reaction.