Electrolysis Flashcards
What is electrolysis?
The breaking down of a substance using electricity
What is an electrolyte?
A molten or dissolved ionic compound
What happens during electrolysis?
Oxidation and reduction
Oxidation
Loss of electrons
Reduction
Gain of electrons
What is a cation and what is it attracted to?
A positive ion in electrolyte that is attracted to cathode, which is a negative electrode
What is an anion and what is it attracted to?
A negative ion in electrolyte that is attracted to anode, which is a positive electrode
Which equations show transfer of electrons during reactions?
Half equations
How do you write half equations?
Put oxidised or reduced subject to one side of the arrow and the subject it gets oxidised or reduced to on the other, balance up the number of atoms, and then add electrons on to one side to balance the charges
Why can’t an ionic solid be electrolysed?
Because its ions are in fixed positions and can’t move
Ions aqueous solutions are divided into
Hydrogen (H+) and Hydroxide (OH-)
At the cathode, if the metal ions are more reactive than hydrogen ions then…
Hydrogen gas will be produced
At the cathode, if the metal ions are less reactive than hydrogen ions then…
A solid layer of pure metal will be produced
At the anode, if hydroxide and halide ions are present then…
Molecules of chlorine, bromine and iodine will be formed
At the anode, if no halide ions are present then..
Oxygen gas is produced
