c3 chemicals in our lives – risks & benefits lesson 7: making alkalis
TRANSCRIPT
C3 Chemicals in Our Lives – Risks & Benefits
Lesson 7: Making Alkalis
ObjectivesMUST describe the first method of manufacturing alkali and the pollution problems it caused
SHOULD explain how one of the pollutants became a source of a useful substance
Key WordsYou need to be able to define the
following:
Textbook Answers1) Salt was too expensive to use industrially because
of the salt tax; an Act ended the tax in 1823.2) Raw materials – salt, coal, limestone; a factory
site; workers; buyers.3) Affected by the fumes of hydrogen chloride and
hydrogen sulphide generated by the process.4) The alkali manufacturers wouldn’t spend money
to clean up their factories if they weren’t forced to.5) Hydrogen and chlorine are gases, colourless and
green respectively; chlorine is a bleach; hydrochloric acid is a solution and is a strong acid.
6) Alkali manufacturers were encouraged to collect as much hydrochloric acid as possible to increase their profits; the factory surroundings were less polluted; people were healthier.
Worksheet AnswersActivity 3 (High demand)1) Chlorine was valuable commodity and
there was lots of waste hydrochloric acid from the alkali industry; chlorine is a green gas and a bleach; hydrochloric acid is a colourless solution and a strong acid.
2) Hydrogen in the hydrochloric acid is oxidised by gaining oxygen to form water; chlorine is oxidised by loss of hydrogen.
3) Yes and no; the Gossage method had been available for years and there was demand for chlorine; the alkali manufacturers needed the spur of the law to improve their works.
Practical Answers
Practical AnswersPart D
1)sodium carbonate + hydrochloric acid sodium chloride + carbon dioxide + water
2)hydroxide + acid salt + water; carbonate + acid salt + carbon dioxide + water
3)a) potassium hydroxide + nitric acid potassium nitrate + water
b) sodium hydroxide + sulfuric acid sodium sulfate + water
c) sodium carbonate + sulfuric acid sodium sulfate + carbon dioxide + water
d) potassium carbonate + nitric acid potassium nitrate + carbon dioxide + water
e) calcium hydroxide + hydrochloric acid calcium chloride + water