Salt

Question 0

How is salt mined from Cheshire?

Answer 0

Rock salt is deposited underground from ancient seas
Rock salt is mixture of salt and impurities
Solution mining - hot water pumped underground to dissolve salt
When finished mining must fill holes or get subsidence
Raw rock salt used on roads, separated for use on food, making chemicals

Question 1

What 2 methods are used to create salt (NaCl)?

Answer 1

Evaporating sea water (hot countries)

Mined - cold countries

Question 2

Salt used for making chemicals has to be cleaned - what method is used?

Answer 2

Electrolysis

Question 3

What does electrolysis of brine give?

Answer 3

Hydrogen, at negative cathode - reduction reaction
chlorine, at positive anode - oxidation reaction
sodium hydroxide (NaOH), formed from ions left in solution

Question 4

What happens in the Chlor-alkali industry?

Answer 4

Electrolysis of brine. Products used for….
Hydrogen - Making ammonia and margarine!
Chlorine - disinfect water, make plastics, solvents
Sodium hydroxide - soap, bleach