Making soluble salts Flashcards
Making soluble salts using an acid and an insoluble base
1) React an acid with one of the ions you want in the salt with an insoluble base that contains the other required ion.
2) Heat the acid in a boiling hot water bath-this speeds up the reaction. This should be done in a fume cupboard to avoid inhaling toxic gases.
3) Add the base to the acid-this will react to produce a soluble salt (and water).
4) You will know when it is in excess and has been neutralized when it sinks to the bottom of the flask.
5) Filter off the solution containing only salt and water
6) Heat it gently with a Bunsen burner and leave the solution to crystallize.
7) Filter the salt one more time and leave it to dry in a warm place.
Making soluble salts using acid/alkali reactions
1) Measure out a set amount of acid into a conical flask using a pipette and add a few drops of indicator.
2) Slowly add the alkali to the acid, using a burette, until you reach the end point-this is when the acid has been neutralized and the indicator changes color.
3) Then carry out the same reaction using the same volumes of alkali and acid but with no indicator, so the salt won’t be contaminated
4) The solution that remains is only salt and water.
5) Slowly evaporate off some water and then leave the solution to crystallize.
6) Filter it off and dry it.
