Electrolytic processes
What are electrolytes?
ionic compounds in the molten state or dissolved in water
What is electrolysis?
a process in which electrical energy, from a direct current supply, decomposses electrolytes
What is the movement of ions during electrolysis?
Positively charged cations migrate to the negatively charged cathode
negatively charged anions migrate to the positively charged anode
What are the products in electrolysis, using inert electrodes, of ...
copper chloride solution
sodium chloride solution
sodium sulfate solution
water acidified with sulfuric acid
molten lead bromide
anode: oxygen is produced cathode: hydrogen produced
anode: bromine is produced cathode: lead produced
anode: chlorine is produced cathode: copper produced
anode: chlorine is produced cathode: hydrogen produced
anode: oxygen is produced cathode: hydrogen produced
How can you predict the product of electrolysis of other binary, ionic compounds in the molten state?
anode
If the anions are halogens the halogen is produced
If the anions are not halogens oxygen is produced
Chloride, bromide, iodine
sulphate, nitrate, carbonate
cathode
If the cations are more reactive than hydrogen then hydrogen is produced
If the cations are less reactive than hydrogen then the metal is produced
K, Mg, Na, Zn, Ca and Fe
Cu, Ag, Au and Pt
Half equation for reactions occurring at the anode and cathode in electrolysis
anode
Oxidation
anion -> non-metal element + electrons
cathode
Reduction
cation + electrons -> metal element
What is oxidation and reduction in terms of electrons?
oxidation is the loss of electrons
reductions is the gain of electrons
What occurs at the cathode and anode?
Oxidation at the Anode
Reduction at the Cathode