1. C4a Acids and Bases
neutral
Acidic Basic (alkaline)
1 2 3 4 5 6 7 8 9 10 11 12 13 14
strong weak neutral weak strong
• Solutions with a pH of ________ than 7 are acids.
• Solutions with a pH of ________ than 7 are alkalis/bases.
• Solutions with a pH of 7 are_________________.
HIGHER
What is an acid?
Look at the formulae of these acids. Hydrochloric acid HCl
Sulphuric acid H2SO4
What element do they all have in common?
Nitric acid HNO3
Phosphoric acid H3PO4
Definition:
What is an alkali?
Definition:
What is the difference between an alkalis and a base?
We often use the words base and alkali to describe the same chemicals. The difference
is that an alkali is a base that _______________ in water.
Alkalis – water
soluble bases
Bases
s

2. Neutralisation
• An acid can be neutralised by adding enough _____________
• An alkali can be neutralised by adding enough _____________
• Adding acid to alkali makes the pH go _________
• Adding alkali to acid makes the pH go _________
General equation for neutralisation:
HIGHER Ionic equation for neutralisation:
Uses of sulfuric acid:
1.
2.
3.

3. Making Salts
Summary
Everything on this page has been studied before but if it is not familiar you MUST learn
it!
Acids to Learn
Hydrochloric acid HCl
Sulphuric acid H2SO4
Nitric acid HNO3
Phosphoric acid H3PO4
Alkalis – water
Salts soluble bases
Compounds formed between
a metal and the non-metal
part of an acid in a
neutralisation reaction
Bases
Acid Name of salt
HCl chloride
H2SO4 sulphate
HNO3 nitrate
H3PO4 phosphate
metal + acid salt + hydrogen
metal oxide + acid salt + water
metal hydroxide + acid salt + water
Metal carbonate + acid salt + water + carbon dioxide

4. Reacting acids with bases and carbonates
The following are all of the names and symbols that the examiners can expect you to know.
Any of these acids could react with any of the bases or carbonates in a neutralisation reaction
Acids Bases Carbonates
sulfuric acid potassium hydroxide sodium carbonate
nitric acid sodium hydroxide calcium carbonate
hydrochloric acid copper oxide
ammonia
Acids Bases Carbonates
H2SO4 KOH Na2CO3
HNO3 NaOH CaCO3
HCl CuO
NH3
Reactions with Sulfuric Acid Don’t forget state symbols: (aq) (g) (s) (l)
sulfuric acid + potassium hydroxide + water
H2SO4 (aq) + KOH(aq) + H2O(l)
sulfuric acid + sodium hydroxide + water
H2SO4 (aq) + NaOH (aq) + H2O(l)
sulfuric acid + copper (II) oxide + water
H2SO4 (aq) + CuO(s) + H2O(l)
sulfuric acid + ammonia
H2SO4 (aq) + NH3(aq)
sulfuric acid + sodium carbonate + water + carbon dioxide
H2SO4 (aq) + Na2CO3 (s) + H2O(l) + CO2 (g)
sulfuric acid + calcium carbonate + water + carbon dioxide
H2SO4 (aq) + CaCO3 (s) + H2O(l) + CO2 (g)

5. Do
yo
bes ur
Reactions with Hydrochloric Acid t, d
on’t
pan
Hydrochloric acid + potassium hydroxide ic!
HCl(aq) + KOH (aq)
Hydrochloric acid + sodium hydroxide
HCl(aq) + NaOH (aq)
Hydrochloric acid + copper (II) oxide
HCl(aq) + CuO (s)
Hydrochloric acid + ammonia
HCl(aq) + NH3(aq)
Hydrochloric acid + sodium carbonate
HCl(aq) + Na2CO3 (s)
Hydrochloric acid + calcium carbonate
HCl(aq) + CaCO3 (s)
Reactions with Sulfuric Acid
nitric acid + potassium hydroxide
nitric acid + sodium hydroxide
nitric acid + copper (II) oxide
nitric acid + ammonia
nitric acid + sodium carbonate
nitric acid + calcium carbonate
If you got through that lot turn to your nearest neighbour and give them a well deserved high-5 !

6. small
beaker
Changing the pH
small funnel
dilute hydrochloric
1. Use a measuring cylinder to transfer acid
burette clamp
30 cm3 of dilute sodium hydroxide
solution to a 250 cm3 beaker.
2. Fill a burette with dilute hydrochloric
acid as shown in the diagram. By turning
the burette tap slightly check that the
solution is able to drip out of the tap
steadily. Close the tap and record the 100 cm3 beaker
reading on the burette. (acting as a drip-
tray)
Volume of HCl added pH of solution Volume of HCl pH of solution
from burette in conical flask added from burette in conical flask
0 15.5
0.5 16.0
1.0 16.5
1.5 17.0
2.0 17.5
2.5 18.0
3.0 18.5
3.5 19.0
4.0 19.5
4.5 20.0
5.0 20.5
5.5 21.0
6.0 21.5
6.5 22.0
7.0 22.5
7.5 23.0
8.0 23.5
8.5 24.0
9.0 24.5
9.5 25.0
10.0 25.5
10.5 26.0
11.0 26.5
11.5 27.0
12.0 27.5
12.5 28.0
13.0 28.5
13.5 29.0
14.0 29.5
14.5 30.0
15.0

7. Analysis of experiment
1. Describe how the pH changes over the course of the experiment as the acid is
added to the alkali.
2. On the graph of your data mark the point on the curve where the pH is 7. What do
you notice about the position of this point?
3. At what point on your graph is acid in excess? Explain your answer. (H)
4. The products of this neutralisation reaction are sodium chloride solution and
water. Write a word equation for the reaction.
5. Write a symbol equation for the reaction. (H)
6. Suggest how the pH of a dilute solution of hydrochloric acid changes when a
solution of sodium hydroxide is added to it until the sodium hydroxide is in excess.
(H)