c6.1 - introduction to electrolysis

what does electrolysis do

breaks down a substance using electricity

when can ionic compounds only be electrolysed

when molten or in an aqueous solution (in water)

why can ions only be electrolysed when molten or aqueous

as then their charged particles are free to move and carry their charge to the electrodes

what is the negative electrode in electrolysis

cathode

what is the positive electrode in electrolysis

anode

what are electrodes made of

inert material so the compound doesn’t react with it

give examples of inert electrode material

graphite or platinum

what are ionic compounds

a metal and a non metal bonded ionically by donating and taking outer shell electrons to become stable. the negative ions are attracted to positive ions.

why do we need electricity in electrolysis

to give energy to break the ionic bonds

what kind of melting point do ionic substances have

high

when do we use electrolysis

when displacement isn’t possible

when is displacement not possible

when an element is above carbon in the reactivity series

show the reduction of lithium

Li+ + e- —> Li

show the oxidation of chlorine

Cl + e- —> Cl-

can you use negative signs when showing oxidation and reduction in ionic compounds

no, you must always use a + sign and adjust accordingly

electrolysis diagram

when an ionic compound is molten or aqueous and can conduct electricity what is it called

electrolyte