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AQA GCSE SCIENCE - C2 6 - Electrolysis




Electrolysis
a) Electrolysis is the decomposition of a substance to give simpler substances.
The substance being electrolysed has to be an ionic compound.
b) The substance being decomposed is called the electrolyte.
c) In electrolysis the electric current enters and leaves the…

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AQA GCSE SCIENCE - C2 6 - Electrolysis




Here is what happens during electrolysis:

Positively charged ions move to the negative electrode during electrolysis.
They receive electrons and are reduced.
Negatively charged ions move to the positive electrode during electrolysis.
They lose electrons and are oxidised.

Predicting the products of…

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AQA GCSE SCIENCE - C2 6 - Electrolysis




The reactivity series of metal - carbon and hydrogen are not metals, but they are
shown for comparison
So the electrolysis of copper chloride solution produces copper at the negative
electrode. But the electrolysis of sodium chloride solution produces hydrogen.

At the…

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AQA GCSE SCIENCE - C2 6 - Electrolysis




copper chloride, CuCl2 copper chlorine

copper sulfate, CuSO4 copper oxygen

sodium chloride, NaCl hydrogen chlorine

hydrochloric acid, HCl hydrogen chlorine

sulfuric acid, H2SO4 hydrogen oxygen

Purification of copper
Copper is a good conductor of electricity, and is used extensively to make electrical…

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AQA GCSE SCIENCE - C2 6 - Electrolysis




Electrolysis of sodium chloride solution
These three products - hydrogen, chlorine and sodium hydroxide - have important
uses in the chemical industry:

Hydrogen
making ammonia
making margarine

Chlorine
killing bacteria in drinking water
killing bacteria in swimming pools
making bleach
making disinfectants…

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AQA GCSE SCIENCE - C2 6 - Electrolysis




At the negative electrode
Positive ions gain electrons at the negative electrode, so are reduced.
In aluminium extraction: Al3+ + 3e- Al
In copper purification: Cu2+ + 2e- Cu
Electrolysis of sodium chloride solution: 2H+ + 2e- H2

At the positive electrode…

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