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electrolysis &electrolysis of aqueous solution (metals can be…
electrolysis &electrolysis of aqueous solution
electrolysis means splitting up with electricity
3) the positive ions in the electrolyte will move towards the cathode and gain electrons
4) the negative ions in the electrolyte will move towards the anode and lose electrons
2) the ions move towards the electrodes where they react and the compound decompose
5) this creates a flow of charge through the electrolyte as ions travel to the electrodes
1) during electrolysis an electric current is passed through an electrolyte the electrolyte is a molten or dissolved ionic compound
6)as ions gain or loose electrons they form the unchanged element and are discharged from the electrolyte
electrolysis of molten ionic solids forms elements
3) molten ionic compounds are always broken up into their elements a good example of this is the electrolysis of molten lead bromine
4) the electrodes should be made of an inert material so they don't react with the electrolyte
2) molten ionic compounds can be electrolysed because the ions can move freely and conduct electricity
5) positive metal ions are reduced to the elements at the cathode
1) an ionic solid cant be electrolysed because the ions are in fixed position and cant move
6) negative non metals ions are oxidised to the elements at the anode
metals can be extracted from their ores using electrolysis
4) the positive al3+ ions are attracted to the negative electrode where they each pick up three electrons and turn them into neutral aluminium atoms these then sink to the bottom of the electrolysis tank
5)the negative o2- ions are attracted to the positive electrode where they each lose two electrons the neutral oxygen atoms will then combine to form o2 molecules
3) the molten mixture contains free ions so its conducts electricity
at the negative electrode
1) metals form positive ions so they are attracted to the negative electrode
2) so aluminium is produced at the negative electrode
2)Aluminium oxide has a very high melting temperature so its mixed with cryolite to lower the melting point
at the positive electrode
1) non metals form negative ions so they are attracted to the positive electrode
2) so oxygen is produced at the positive electrons
1) aluminium is extracted from the ore bauxite by electrolysis bauxite contains aluminium oxide AL203
overall equations
aluminate oxide ---> aluminium + oxygen
it may be easier to discharge ions from water than the solute
2) which ions are discharged at the electrode when the solution is electrolysed will depend on the relative reactivity of all the ions in the solution
cathode
at the cathode if h+ ions and metal ions are present hydrogen gas will be produced if the metal ions form an elemental metal that is more reactive than hydrogen
if the metal ions form an elemental metal that is less reactive than hydrogen a solid layer of pure metal will be produced instead which will coat the cathode
1) in aqueous solutions as well as the ions form the ionic compounds there will be hydrogen ions and hydroxide ions from the water
anode
at the anode if oh- and halide ions are presented molecules of chlorine bromine or iodine will be formed