4.7        describe how to prepare soluble salts from acids

Method 1 - acid and insoluble solid, e.g. copper(II) oxide + sulfuric acid to make copper(II) sulfate

1)   Heat the acid in a beaker (a suitable volume of acid would be 50 cm3)

2)   Add the solid a little at a time until it is in excess (i.e. there is no evidence of further reaction on adding more solid).

3)   Filter off the excess solid.

4)   Transfer the liquid to an an evaporating basin and boil off two thirds of the water.

5)   Leave so the rest of the water slowly evaporates, leaving crystals of the salt.

6)   Dry the solid, if necessary, in a drying oven.

Method 2 - acid and an alkali in solution, e.g. nitric acid and sodium hydroxide to make sodium nitrate

1)   Do a titration (See Section 4.9) to find out exactly how much of each solution is needed for neutralisation.

2)   React the volumes of acid and alkali determined in step 1), but without using an indicator this time.

3)   Do steps 4) to 6) from Method 1.