electrolysis-2

What is electrolysis

The process of separating ionic compounds into their pure elements by passing electric current through electrolyte

When is electrolysis used to extract metals

If a metal is too reactive(than carbon ) to be extracted with carbon , then electrolysis can be used to extract it

In what cases does electrolysis only work in

It ions are free too move( when Molten)

If a solid metal the ions are fixed, when molten the ions are free too move move

What do we need to use to extract metal into pure metal

Use reduction

The easiest way to use reduction is with carbon however you need to use electrolysis for metals more reactive than copper

Describe the process of extracting aluminium by electrolysis

1) purify the aluminium oxide from the bauxite that we mined from the ground.2) melt the aluminium oxide to make it molten. Al2O3 Is hard to melt because it has a very high melting point at over 2000° C so first we need to mix the aluminium oxide with Cryolite-cryolite lowers the melting point.4) Then it can be melted

Now set it up for electrolysis

1)need a beaker to hold the molten aluminium oxide (elecrolyte) then we need the electrodes which act as conductors through which electrons can pass. There are two electrodes the cathode and anode which are connected using a wire and there was a power source where with a battery so electrons can flow in a complete circuit.

For the extraction of aluminium by electrolysis what happens at each electrode

The positive aluminium ions are attracted to the negative electrode where they each pick up three electrons and turn into neutral aluminium atoms these sink to the bottom of the electrolysis tank. The negative oxygen ions are attracted to the positive electrode whether each lose two electrons the neutral oxygen Atoms combined to form oxygen molecules. Some of the oxygen produce reacts with the carbon and the electron to produce carbon dioxide

Why are electrodes made of carbon (graphite )

They are good conductor of electricity