Use a copy of the Periodic Table where you need one.
Which salt is insoluble in water?
Source: Learners' Alley, Salts slides
Which method is best for preparing potassium sulfate?
Source: Learners' Alley, Salts slides
Answer these questions about salts.
Source: Learners' Alley, Salts slides
Which of the following pairs of reagents should be mixed to prepare a sample of lead(II) sulfate salt?
Source: 2023 GESS Sec 3 End-of-Year P1 Q32
When preparing a salt by titration, the experiment is usually repeated without the indicator after the volume needed for neutralisation has been found. Why is the indicator left out when preparing the salt crystals?
Source: 2023 GESS Sec 3 End-of-Year P1 Q33
Which of the following does not show suitable reagents for preparing the named salt?
| salt | reagents | |
|---|---|---|
| A | copper(II) sulfate | copper(II) carbonate + sulfuric acid |
| B | lead(II) nitrate | lead(II) oxide + nitric acid |
| C | magnesium chloride | magnesium nitrate + hydrochloric acid |
| D | zinc chloride | zinc hydroxide + hydrochloric acid |
Source: 2024 SMSS Sec 3 End-of-Year P1 Q13
How can a pure sample of lead(II) sulfate be obtained from lead(II) carbonate?
Source: 2024 SMSS Sec 3 End-of-Year P1 Q15
Titration of an acid against a base is a method often used in the preparation of salts. Which properties of the acid, the base and the salt are required if this method is to be used?
| acid | base | salt | |
|---|---|---|---|
| A | insoluble | insoluble | insoluble |
| B | soluble | insoluble | insoluble |
| C | soluble | soluble | insoluble |
| D | soluble | soluble | soluble |
Source: 2023 XMS Sec 3 WA3 Q3
Salt ST is to be prepared by reacting the carbonate of S with the acid HT using titration. What are the solubilities of the carbonate, the acid and the salt?
| carbonate of S | acid HT | salt ST | |
|---|---|---|---|
| A | insoluble | soluble | insoluble |
| B | insoluble | soluble | soluble |
| C | soluble | insoluble | insoluble |
| D | soluble | soluble | soluble |
Source: 2023 HYSS Sec 3 End-of-Year P1 Q9
An excess of barium chloride solution is added to a solution of magnesium sulfate and a white precipitate is formed. The mixture is then filtered. Which solution would not produce a precipitate when added to the filtrate?
Source: 2024 SMSS Sec 3 End-of-Year P1 Q16
Darren wants to prepare a pure, dry sample of zinc nitrate. He decides to use zinc oxide and nitric acid.
Source: Woodlands Prelim P2 Q(b)
The table shows information about the preparation of pure samples of two solid salts.
| salt | reagents used | method used to prepare the salt | method used to obtain the solid from the reaction mixture |
|---|---|---|---|
| potassium chloride | 1: dilute hydrochloric acid 2: .......... | .......... | crystallisation |
| lead(II) sulfate | 1: dilute sulfuric acid 2: .......... | precipitation | .......... |
Source: 2024 CHS Sec 3 End-of-Year Section B Q6(a)
Csilver chloride[1]
Silver chloride is one of the two insoluble chlorides. All ammonium salts, all nitrates and all sodium salts are soluble.
Ctitration of aqueous potassium hydroxide with dilute sulfuric acid[1]
Potassium sulfate and all its starting materials are soluble, so titration is used. Potassium reacts violently with acids, an excess of soluble potassium carbonate cannot be filtered off, and precipitation is only for insoluble salts.
Any two of barium sulfate, lead(II) sulfate and calcium sulfate. [1]
So that all the acid is used up and the salt is not contaminated with acid. [1]
Titration of dilute hydrochloric acid with aqueous sodium hydroxide. [1]
Ba2+(aq) + SO42−(aq) → BaSO4(s) [1]
Dlead(II) nitrate and sodium sulfate[1]
Lead(II) sulfate is insoluble, so it is made by precipitation from two solutions. Lead(II) nitrate and sodium sulfate are both soluble.
With lead metal or lead(II) carbonate, a coating of insoluble lead(II) sulfate stops the reaction. Lead(II) chloride and barium sulfate are both insoluble, so they do not react.
BThe indicator is an impurity and will lead to impure crystals.[1]
The indicator is a foreign substance in the reaction mixture, so it would contaminate the salt.
Cmagnesium chloride from magnesium nitrate and hydrochloric acid[1]
Magnesium nitrate and hydrochloric acid are both soluble and do not react to form a precipitate, so no magnesium chloride is separated. The other pairs are an acid with an insoluble carbonate, oxide or hydroxide.
CAdd lead(II) carbonate to dilute nitric acid, then add dilute sulfuric acid, filter the mixture and wash the residue.[1]
First make soluble lead(II) nitrate, then precipitate insoluble lead(II) sulfate with sulfuric acid. The precipitate is the residue, so it is washed, not crystallised. Adding lead(II) carbonate straight to sulfuric acid forms a coating of lead(II) sulfate that stops the reaction.
Dall soluble[1]
Titration is used when the acid, the base (an alkali) and the salt are all soluble.
Dall soluble[1]
Titration needs every reactant and the salt to be soluble, so the carbonate must be a sodium, potassium or ammonium carbonate.
Bpotassium nitrate[1]
The filtrate contains excess Ba2+ and Cl− ions, with Mg2+. Sulfate gives barium sulfate, silver ions give silver chloride and carbonate gives insoluble carbonates. All nitrates and potassium salts are soluble.
Add excess zinc oxide to dilute nitric acid and stir until no more zinc oxide dissolves. Filter to remove the excess zinc oxide as the residue, and collect the filtrate (aqueous zinc nitrate). [1]
Heat the filtrate to evaporate most of the water and obtain a saturated solution, then allow it to cool so that the salt crystallises. [1]
Filter to collect the crystals, wash them with a little cold distilled water and dry them between a few sheets of filter paper. [1]
Potassium chloride: reagent 2 is aqueous potassium hydroxide or potassium carbonate [1], and the method is titration. [1]
Lead(II) sulfate: reagent 2 is aqueous lead(II) nitrate [1], and the solid is obtained by filtration. [1]