EXPERIMENTAL: PREPARATION OF WATER-SOLUBLE SALTS USING NEUTRALIZATION 
AND METAL DISPLACEMENT REACTIONS
Introduction Reactions used to prepare salts, which are ionic compounds made up of ions other than H1+, OH1-, or O2-, include neutralization (i.e., the reaction between an acid and a base), displacement (i.e., when a more reactive element displaces a less reactive element from its compound), and precipitation (i.e., when two soluble ionic compounds react to form a precipitate). Shown below are equations which summarize exemplars of these three reaction types; neutralization (1 - 4), displacement (5 and 6), and precipitation (7).
(1) NiO(s) + 2HCl(aq) 覧覧覧覧覧覧覧 NiCl2(aq) + H2O(l) (2) Mg(OH)2(s) + H2SO4(aq) 覧覧覧覧覧 MgSO4(aq) + 2H2O(l) (3) PbCO3(s) + 2HNO3(aq) 覧覧覧覧覧覧 Pb(NO3)2(aq) + H2O(l) + CO2(g) (4) 2NH3(aq) + H33PO4(aq) 覧覧覧覧覧 (NH4)2HPO4(aq) (5) Zn(s) + H2SO4(aq) 覧覧覧覧覧覧覧 ZnSO4(aq) + H2(g) (6) 2Al(s) + 3Zn(NO3)2(aq) 覧覧覧覧覧 2Al(NO3)3(aq) + 3Zn(s) (7) 2KOH(aq) + FeSO4(s) 覧覧覧覧覧覧 2Fe(OH)2(s) + K2SO4(aq)
Whereas a precipitation reaction is commonly used for the preparation of an insoluble salt, neutralization and metal displacement reactions are often those of choice for the preparation of water-soluble salts. [... K > Ca > Na > Mg > Al > Mn > Zn > Fe > Co > Pb > (H) > Cu > Ag ..]
First, using a neutralization reaction, you are required to prepare
crystals of either copper(II) ethanoate or copper(II) chloride, using
appropriate starting materials from: aqueous ethanoic acid; aqueous
sulfuric acid; aqueous hydrochloric acid; copper; copper(II) oxide;
copper(II) carbonate; copper(II) sulfate; and copper(II) nitrate.
And second, using a metal displacement reaction, you are required to prepare crystals of a second ethanoate or chloride. One starting material should be some of your freshly prepared copper(II) ethanoate or copper(II) chloride; and the other should be a suitably correct choice from: cobalt; cobalt(II) carbonate; manganese; manganese(III) carbonate; silver; silver(I) carbonate; zinc; and zinc carbonate.
Before starting your experimental work, be sure to complete this flow
chart - which should summarize your choice of reactants and products.
Method (1) - via a Neutralization Reaction
1.  Collect the following (for Methods 1 and 2): safety glasses; Bunsen
burner kit; 100 cmウ glass beaker; measuring cylinder (25 cmウ); stirring
rod; filter funnel; 2 filter papers; retort stand and clamp; 2 splints;
evaporating dish; 2 petri dishes; pH paper; and starting materials.
2.  Set up, ready for use, the Bunsen burner kit and the filtration
apparatus; until required, the evaporation and petri dishes should be
lying face downwards on tissue paper.
3.  Using the measuring cylinder, place 25 cmウ of dilute acid into the
beaker equipped with a stirring rod; check the pH of the acid.
4.  Warm the acid using a small Bunsen flame (or a boiling water-bath
if a metal is used as one of the starting materials).
5.  [Throughout this step, you should be prepared to switch off the 
Bunsen if the reaction becomes too vigorous.  Furthermore, you should 
try and maintain a volume of about 25 cmウ for the reaction mixture, by 
adding small volumes of water as and when required.]  To the warm acid, 
add the solid starting material in small portions until it is in slight 
excess; that is, until no more dissolves and the pH paper no longer 
turns red.
6.  [The reaction mixture contains an excess of insoluble starting 
material and the required salt dissolved in water.]  Dampen the filter 
paper and, using the stirring rod as a guide, filter the warm reaction 
mixture into the evaporating dish; it is good technique to wash both 
the beaker and filter paper with a little water.
7.  [The filtrate (and washings) should contain only the required salt
dissolved in water.]  Transfer half the filtrate to a petri dish; cover 
this dish with paper, (labelled with name, contents, and date), and 
allow the solution to crystallize at room temperature.
8.  Using Sellotape, attach a small sample of these crystals to this
worksheet; to be safe, you must assume the compound is toxic.
Method (2) - via a Displacement Reaction 1. To the second half of the filtrate (see step 7 above), stir in the metal powder in small portions until in slight excess; that is, until there are no more changes to the supernatant. 2. Dampen the filter paper and, using the stirring rod as a guide, filter this reaction mixture into a second petri dish .... 3. Cover this dish with paper, (labelled with name, contents, and date), and then allow the solution to crystallize at room temperature. 4. Using Sellotape ............ you must assume the compound is toxic.
Notes Method 1 can be used to prepare most water-soluble salts, providing the solid starting material, (i.e., metal, oxide, hydroxide, or carbonate), is insoluble in water. However, a 'titration' method must be used if the starting material is soluble in water (i.e., all Group 1 compounds, ammonium compounds, nitrates, and ethanoates).
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