Revision exercise Acid An acid has a sour taste. Lemon juice is
an example of an acid. An acid has a pH value between 0 and 7 Base
Indicator Litmus pH
Slide 3
Stage 1 Use the 10cm 3 pipette and pipette filler to measure
out 20cm 3 of sodium hydroxide (NaOH) and put it in the conical
flask Make sure to match the bottom of the meniscus with the scale
on the pipette.
Slide 4
Stage 2 - Titration Titrations are used to very accurately add
a certain amount of an acid to a base. Fill the burette accurately
with 50cm 3 of Hydrochloric acid (HCl) Remember to line up bottom
of meniscus 12 3
Slide 5
Stage 3 - Evaporation Place the resultant solution from the
final titration into an evaporating dish Put the dish on a gauze on
a tripod Heat the dish with a Bunsen burner until all the liquid is
gone
Slide 6
To titrate hydrochloric acid (HCl) against sodium hydroxide
(NaOH) and prepare a sample of salt NaCl For our experiment we are
using 1M HCl with a pH value of 0 And 1M NaOH with a pH value of 14
We add the HCl to the NaOH What do you think will happen to the pH
value of the resulting solution?
Slide 7
To titrate hydrochloric acid (HCl) against sodium hydroxide
(NaOH) and prepare a sample of salt NaCl Stage 1 Stage 2 Stage 3 12
3
Slide 8
Discussion of results Titration No. Volume of HCl added (cm 3 )
We have just performed a neutralisation reaction. The addition of
the HCl lowered the pH of the solution to 7 Neutralisation ACID +
BASE = SALT + WATER HCl + NaOH = NaCl + H 2 O Can you think where
this type of reaction might be useful in everyday life?