Name :
_____________________
Teacher: ______________________
Acids, bases and salts – an introduction!
Hydrogen, hydrochloric acid, pH, water, pure water, neutral, hydroxide ions,
hydrogen,
An example of an acid is _____________ _________.
When acids dissolve in water they form ______ ions (H +).
Alkalis are bases when dissolved in _______.
Alkalis form __________ (OH-) when dissolved in water.
The _____ scale tells us which kind of ion is present.
pH stands for the % _________ in solution.
A ________ solution has a pH of 7
An example of a neutral solution is _____ _______.
In the space below write a symbol equation to describe what happens when
hydrochloric acid is mixed with water.
In the space below write a symbol equation to describe what happens when
sodium hydroxide is mixed with water.
Challenge yourself:
What do you think happens when we add equal quantities of acid and base
together?
1
Acid and alkali strength
You probably used universal indicator to test acids and alkalis. This
solution (or paper) is really useful as it allows us to tell where on the
pH scale something is.
You are going to test some solutions and work out whether they are
acid or alkaline.
But first we need to look at how universal indicator (UI) works.
Can you colour in this chart to show the COLOUR that UI turns in
different solutions?
pH
1
Colour
2
3
4
5
6
7
8
9
10
11
12
Anything with a pH of ………………………………….. is an acid
Anything with a PH of …………………………………… is an alkali
pH …………………… is neutral
What happens to the strength of an acid as the pH decreases?
…………………………………………………………………………………………………………………………….
What happens to the strength of an alkali as the pH increases?
…………………………………………………………………………………………………………………………….
I would describe pH 5 as a …………………… ……………………………..
I would describe pH 14 as a …………………… ……………………………..
2
13
14
Experiment:
For this experiment you are going to use red and blue litmus paper and
either universal indicator solution or paper. You need to test each
solution and match the colour change to the pH scale to discover the
pH of the solution. Record your results in the table below.
Substance
Red
Blue
Universal pH
Red
Type of
litmus
litmus indicator
cabbage substance
Distilled
water
Bicarbonate
of soda
Hydrochloric
acid
Salt solution
Sodium
hydroxide
Lemon juice
Sulphuric acid
Orange juice
Stomach
powder
solution
Toothpaste
Toilet cleaner
Tap water
Vinegar
3
Don’t forget that everyday substances are acidic. This is why you need
to clean your teeth kids… so that the acid in the food you eat does not
erode your tooth enamel away. What do you notice about the pH of
toothpaste?.................................................................................
Why do you think this might be?...............................................................
………………………………………………………………………………………………………………………..
Information
Main Laboratory Acids
Acids found at home:
Citric acid
Vinegar (acetic acid)
Coke (phosphoric acid)
Vitamin C (ascorbic acid)
Name
Formula
Hydrochloric Acid
Nitric Acid
Sulphuric Acid
HCl(aq)
HNO3(aq)
H2SO4(aq)
Acids taste SOUR
Acids contain HYDROGEN IONS H +
(aq)
Main Laboratory Alkalis
Alkalis found at home:
Name
Sodium Hydroxide
Potassium Hydroxide
Calcium Hydroxide
Ammonium Hydroxide
Formula
NaOH(aq)
KOH (aq)
Ca(OH)2(aq)
NH4OH(aq)
Alkalis feel SOAPY
Alkalis contain HYDROXIDE IONS OH – (aq)
Soap
Toothpaste
Shampoo
4
Past paper question
5
Summary of the things that you have learnt this lesson- in
your own words
6
Acids and Metals
Do you remember the metal reactivity series?
Write down as many metals as you can think of with the most reactive
at the top and the least reactive at the bottom:
Try and do it WITHOUT looking at your Periodic table
Your list
Actual list
Now compare this with the list that your teacher comes up with and
write these in the right hand column .
Are there any surprises?
7
Experiment:
You are going to use hydrochloric acid and a selection of metals and see
what happens when you react them together. Wear goggles!
Use about 1 cm depth of acid in the test tube and half a spatula of
metal.
Write down everything that you observe (you may want to feel the
tubes). Also test the gas that is produced.
Metal
Observations
Reactivity
Copper
Magnesium
Iron
Zinc
Aluminium
Once you have finished write down the order of the reactivity of the
metals. Use 1 for the most reactive.
What gas is produced in this reaction?.........................................................
How do you test for this gas?........................................................................
8
Equations:
We need the equations to explain what is happening
First of all we need to know what we have in order to be able to write
equations....... Metals are easy, they are on the left hand side of the
periodic table.
What do all acids contain?.........................................................................
When a metal and an acid react together they make salts.
SALT - a SALT is formed when the Hydrogen of an Acid is
replaced by a metal
Naming SALTS
Remember metals (except copper and some others) push out (displace) the hydrogen of
acids to make SALTS.
ACID
TYPE of SALT made
Hydrochloric acid
HCl(aq)
CHLORIDES e.g. sodium chloride
NaCl(s)
Sulphuric acid
H2SO4(aq)
SULPHATES e.g. magnesium sulphate
MgSO4(s)
Nitric acid
HNO3(aq)
NITRATES e.g. potassium nitrate
KNO3(s)
Carbonic acid
H2CO3(aq)
CARBONATES e.g. zinc carbonate
ZnCO3(s)
Phosphoric acid
H3PO4(aq)
PHOSPHATES e.g. calcium phosphate
Ca3(PO4)2(s)
9
So, a SALT contains:
And
a CATION e.g. Na+ (usually from a METAL)
an ANION e.g. Clfrom an ACID e.g. hydrochloric acid HCl(aq)
We will not write an equation for copper as it doesn’t react. The first
one has been done for you as an example
1. magnesium + hydrochloric acid 
magnesium + hydrogen
…chloride....
Mg
+
2. Iron
2HCl
MgCl2

+ H2
+ hydrochloric acid  ……………………….. + ……………………………
……………………….
Fe
+
3. Zinc
HCl
 ……………………….. + ……………………………
+ hydrochloric acid  ……………………….. + ……………………………
……………………….
Zn
+
HCl
 ……………………….. + ……………………………
4. aluminium + hydrochloric acid  ……………………….. + ……………………………
……………………….
Al
5.
+
tin
HCl
 ……………………….. + ……………………………
+ hydrochloric acid  ……………………….. + ……………………………
……………………….
Sn
+
HCl
 ……………………….. + ……………………………
10
Past paper question
The reactions of metals with acids can show the reactivity trend
amongst the metals.
Remember back to your metals topic.... why do you think that you were
not given sodium to react with the hydrochloric acid today?
.........................................................................................................................
Write out the general equation for the reaction of a metal with an
acid:
..................... + ......................  .....................
................. + ................................
11
Extension Equations:
You did equations for hydrochloric acid, now what if you had a
different starting acid? You may need to look back at your notes to
check that you get the formulae of these compounds correct
1. magnesium + nitric acid

……………………….. + ……………………………
……………………….
Mg
2. Iron
+
HNO3
+ nitric acid
 ……………………….. + ……………………………

……………………….. + ……………………………
……………………….
Fe
+
3. Zinc
HNO3
+ nitric acid
 ……………………….. + ……………………………

……………………….. + ……………………………
……………………….
Zn
+
HNO3
4. aluminium + nitric acid
 ……………………….. + ……………………………

……………………….. + ……………………………
……………………….
Al
5.
+
tin
HNO3
+ nitric acid
 ……………………….. + ……………………………

……………………….. + ……………………………
……………………….
Sn
+
HNO3
 ……………………….. + ……………………………
12
6. magnesium + sulphuric acid 
……………………….. + ……………………………
……………………….
Mg
7. Iron
+
H2SO4
 ……………………….. + ……………………………
+ sulphuric acid
 ……………………….. + ……………………………
……………………….
Fe
+
8. Zinc
H2SO4

……………………….. + ……………………………
+ sulphuric acid 
……………………….. + ……………………………
……………………….
Zn
+
H2SO4
9. aluminium + sulphuric acid
 ……………………….. + ……………………………
 ……………………….. + ……………………………
……………………….
Al
10.
+
tin
H2SO4
+ sulphuric acid
 ……………………….. + ……………………………
 ……………………….. + ……………………………
……………………….
Sn
+
H2SO4
 ……………………….. + ……………………………
13
Neutralisation
Method:
1. Use a measuring cylinder to measure out 20cm3 of acid
and pour into the burette.
2. Measure 20cm3 of sodium hydroxide into a flask/beaker
3. Add 2-3 drops of Universal indicator with a pipette.
4. Slowly open tap on burette and let the acid drop out.
5. Stop when solution turns green.
6. Pour solution into a petri dish and leave overnight.
7. Note the volume of acid used to neutralise the alkali.
8. Repeat experiment.
Results:
Burette readings
Accurate titrations
Rough titration
End point
Start of titration
Volume of acid used
1st
2nd
3rd
cm3
cm3
cm3
cm3
0.0 cm3
0.0 cm3
0.0 cm3
0.0 cm3
cm3
cm3
cm3
cm3
1.Give the word equation for the neutralization reaction of an acid and a base.
___________ + ___________→_____________+___________
2. Complete the equation for this neutralization reaction:
a) In symbol form HCl
b) In word form
+
NaOH
→
_________ + _________→___________+________
3. A _______________ is a laboratory method used to determine the
concentration of an acid or a _______________ in solution by performing a
_______________ reaction with a standard solution.
14
4. At the ______________ of the titration, the indicator changes color, which
indicates neutralization.
Once neutralized, number of _____________ and number of ____________
are equal.
5.What colour did the solution turn when just enough acid was added?
_____________
6.What colour did the solution turn when too much acid was added?____________
Possible words to use: yellow, sodium hydroxide, titration, NaCl ,salt, green,
neutralization, acid, H20, alkali, water, end, hydrogen ions, hydroxide ions
Reviewing Neutralisation
We did lots of equations for the reactions of metals with acids and now
we need to look at equations for neutralisation.
Word equation:
hydrochloric + sodium
acid
 …………………………….. + ………………………………
hydroxide
…..………………………..
Symbol equation:
HCl
+
NaOH
 …………………………….. + ………………………………
What if we changed the acid?
Word equation:
sulphuric
acid
+
sodium
hydroxide
 …………………………….. + ………………………………
…..………………………..
15
Symbol equation:
H2SO4
+
NaOH
 …………………………….. + ………………………………
sodium
 …………………………….. + ………………………………
Word equation:
nitric
+
acid
hydroxide
…..………………………..
Symbol equation:
HNO3
+
NaOH
 …………………………….. + ………………………………
And what if we change the alkali?
Word equation:
sulphuric
+
acid
potassium  …………………………….. + ………………………………
hydroxide
…..………………………..
Symbol equation:
H2SO4
+
KOH
 …………………………….. + ………………………………
16
And what if we changed both?
Word equation:
hydrochloric + lithium
acid
hydroxide
 …………………………….. + ………………………………
…..………………………..
Symbol equation:
HCl
+
LiOH
 …………………………….. + ………………………………
Preapring a soluble salt -Practical
You are going to make some soluble salt from a largely insoluble base.
Copper oxide is what we can describe as a base.
This is because it is not acidic…. and it acts the same as an alkali when it reacts.
If your exam talks about a base they probably mean a metal oxide.
NB some bases are soluble. This one is not
Collect:
A beaker
Measuring cylinder
Filtration apparatus
Bunsen burner, heatproof mat and tripod
Evaporating basin
Test tube rack
Stirring rod
Hydrochloric acid
Copper oxide and a spatula
1. Put 50 cm3 of acid into the beaker. Warm and stir while adding copper oxide until
all the acid has been used up. Your teacher will help you recognise this point.
2. Filter the mixture using the filtration apparatus and standing the funnel in a test
tube rack.
3. Heat the evaporating basin until crystals begin to form
4. Filter the remaining solution to leave behind the crystals
17
Questions on the practical:
1. Describe what you saw once the acid had been used up
...........................................................................................................
...........................................................................................................
...........................................................................................................
Use the terms in the box for questions 2-4
18
2. Give the property of copper oxide that allows it to be removed by filtering in Stage
2.
...........................................................................................................
3. Name the substance being removed during stage 3
...........................................................................................................
4. Write a word equation to represent the reaction in stage 1. (hint: neutralisation)
......................... + ..........................  ................................ + .............................
......................... ..........................
Past paper question
................................
19
Extension
Use the clues to find out what words you need to find in the word
search.
C
I
R
O
L
H
C
O
R
D
Y
H
N
A
A
C
A
L
C
I
U
M
A
N
O
P
V
S
O
D
I
U
M
G
W
I
C
C
A
U
S
X
C
E
N
H
H
T
R
E
T
A
W
E
I
N
I
T
O
R
P
Q
S
U
R
I
D
D
D
Y
H
A
R
W
U
C
D
M
L
O
E
F
G
T
T
O
L
N
K
L
E
A
S
S
D
E
H
Y
D
R
O
G
E
N
K
E
I
I
M
N
I
T
R
I
C
E
Z
L
C
O
H
Y
D
R
O
X
I
D
E
M
A
P
C
I
R
U
H
P
L
U
S
N
B
Y
1) Hydrochloric acid + copper oxide  copper chloride + _____________ (5)
2) Nitric acid + copper oxide  copper ______________ + water (7)
3) ______________acid + copper oxide  copper sulphate + water (9)
4) An ________________ is a soluble base (6)
5) Hydrochloric acid + _____________hydroxide  sodium chloride + water
(6)
6) Nitric ___________ + potassium hydroxide  potassium nitrate + water (4)
7) Sulphuric acid + ________________  calcium sulphate + hydrogen (7)
8) _______________acid + magnesium oxide  magnesium chloride + water
(12)
9) Bases are metal hydroxides and metal ______________(6)
10) ______________acid + sodium hydroxide  sodium nitrate + water (6)
11) Sulphuric acid + sodium _____________  sodium sulphate + water (9)
12) Hydrochloric acid + zinc  zinc chloride + ___________________ (8)
20
Metal Carbonates and acid
What do you need to put in the test tube to test for carbon dioxide?
..................................................
Describe what you saw when you did this experiment
……………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………
Word equation:
hydrochloric + calcium
acid
carbonate
 …………………… + …………………. + …………………
…..……………
…..…………….
Symbol equation:
HCl
+
CaCO3
 …………………… + …………………. + …………………
21
Do you notice any similarities with this equation and the ones that were
done with the alkali and the base?
This is another type of neutralisation…..
You are now ready to write a summary of these reactions:
These need to be LEARNT and you need to be able to write specific
word and symbol equations for them.
Neutralisation summary
Base
+
Acid

……………………………
+
……………………………
Alkali
+
Acid

……………………………
+
……………………………
Metal
carbonate
+
Acid

…………………… + …………………. + …………………
…..……………
22
…..…………….
Past paper question
23
Extension
24
What is the name given to substances like water that have both acid and base characteristics?
1
2
7
6
4
5
3
11
8
9
10
12
A substance that accepts H+ ions OR a soluble base
A dye that turns red in acid and blue in alkali
Any dye that changes colour at different pHs
The element present in all acids
A substance that dissociates to form hydrogen ions
Another name given to a hydrogen ion
A substance that contains hydrogen and hydroxide ions in equilibrium and is
neutral at pH7
8. An acid is a proton _ _ _ _ _
9. The symbols of the elements present in an alkali
10. The colour litmus paper turns in acid
11. A solution that contains charged particles is described as _ _ _ _ _
12. The colour litmus goes in alkali
1.
2.
3.
4.
5.
6.
7.
Rearrange the shaded letters to answer the question in the title:
_ _ _ _ _ _ _ _ _ _
25
Summary Checklist
Topics
Red
a) be able to classify substances as acidic, alkaline or
neutral in terms of the pH scale, including acid/alkali
strength.
b) investigate the reactions of acids with metals and
explain their observations in terms of the metals'
position in the reactivity series.
c) know that the neutralisation of dilute acids with
bases (including alkalis) and carbonates and that
carbonates effervesce in acid
d) carry out test to identify carbon dioxide gas.
e) prepare crystals of soluble salts, such as copper(II)
sulphate, from insoluble bases and carbonates.
f) be able to write and interpret word equations and
balance chemical equations to describe the
reactions of metals, bases (including alkalis) and
carbonates with the following acids: hydrochloric
acid, nitric acid and sulphuric acid.
26
Amber
Green