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