Neutralising an acid Core Practical
Aim
Powdered calcium hydroxide reacts with hydrochloric acid. Calcium chloride solution
and water are produced:
Ca(OH)2(___) + 2HCl(___) → CaCl2(__) + 2H2O(__)
You will investigate what happens to the pH of a fixed volume of dilute hydrochloric
acid when you add calcium hydroxide to it.
The variables are...
Independent Dependent Control Safety precautions
In order to reduce the risk of this investigation, I will need to___________________
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Method
Equipment needed
3
Using a measuring cylinder add 50 cm (ml) of
dilute hydrochloric acid to the beaker.
Put a piece of universal indicator paper onto
the white tile.
Dip the end of the glass rod into the liquid then
dab onto the indicator paper.
Wait 30 seconds, then match the colour to the
appropriate pH on the pH colour chart, record
the colour and pH in the table
Rinse the glass rod with water.
Measure out 0.3 g of calcium hydroxide
powder onto a ‘weighing boat’ using the
scales.
Add the calcium hydroxide powder to the
beaker, stir, then record the pH of the mixture
using the same method as above.
Add another 0.3g and repeat filling the table
below.
Mass of calcium
hydroxide (g)
0.0
0.3
0.6
0.9
1.2
1.5
1.8
2.1
2.4
Colour
pH