Reactions of acids (i)
1
Metal hydroxide solutions (alkalis), metal oxides and metal carbonates are all bases
they
react with acids in a neutralisation reaction.
ACID
+
BASE
+
SALT
WATER
If the base is a metal carbonate then carbon dioxide is also produced.
Many salts are prepared by neutralisation reactions. The method used to make the salt
depends on its solubility, i.e. whether the salt is soluble or insoluble in water.
(a) The reaction of acid with alkali
ACID
+
ALKALI
SALT
+
WATER
An indicator has to be used to find the volume of alkali required to neutralise a known
volume of acid. The experiment is repeated using the same volume of alkali without the
indicator. To obtain a solid sample of the salt, the salt solution is evaporated to dryness.
Write a word equation for each of the following chemical reactions.
dilute hydrochloric acid / potassium hydroxide solution
dilute hydrochloric acid / potassium hydroxide solution
dilute sulphuric acid / barium hydroxide solution
dilute nitric acid / sodium hydroxide solution
Chemical Changes and Structure
Acids and Alkalis
Reactions of acids (i)
2
(b) The reaction of an acid with a m etal oxide
ACID
+ METAL OXIDE
SALT
+
WATER
This method can be used when the metal oxide is insoluble in water, e.g. copper(II) sulphate
can be prepared by the reaction of copper(II) oxide with sulphuric acid. The metal oxide will
react with the acid but will not dissolve in the neutral solution. If excess metal oxide is added
(more than what is needed to react with all the acid), then the unreacted metal oxide can be
removed from the neutral solution by filtering. The solution (the filtrate) is evaporated to
dryness to obtain a solid sample of the salt.
Write a word equation for each of the following chemical reactions.
dilute hydrochloric acid / copper(II) oxide
dilute sulphuric acid / magnesium oxide
dilute nitric acid / iron(III) oxide
Chemical Changes and Structure
Acids and Alkalis
Reactions of acids (i)
3
(c) The reaction of an acid with a m etal carbonate
ACID + METAL CARBONATE
SALT + WATER + CARBON DIOXIDE
This method can also be used when the metal carbonate is insoluble in water,
e.g. magnesium sulphate can be prepared by the reaction of magnesium carbonate with
sulphuric acid. The method used is the same as that used with an insoluble metal oxide.
Name the gas produced in the reaction of an acid with a metal carbonate.
Write a word equation for each of the following chemical reactions.
dilute hydrochloric acid / magnesium carbonate
dilute sulphuric acid / copper(II) carbonate
dilute nitric acid / iron(III) carbonate
Chemical Changes and Structure
Acids and Alkalis
Reactions of acids (i)
4
Complete the following table by placing each of the following salts in the correct
column.
sodium chloride, copper(II) chloride, lithium sulphate, lead(II) nitrate,
potassium nitrate, calcium sulphate
Can be prepared by
acid/metal oxide reaction
Must be prepared by
acid/alkali reaction
John prepared copper(II) sulphate in the lab. by the reaction of copper(II) oxide with
sulphuric acid; Mary prepared sodium sulphate by the reaction of sodium hydroxide
solution.
Why were different methods used?
Chemical Changes and Structure
Acids and Alkalis