Redox Processes (AHL) 19.1 (General information (Application (metal…
Redox Processes (AHL) 19.1
Faraday's first law
Definition: states that the mass of an element deposited during the electrolysis is directly proportional to the quantity of electricity passing through the electrolysis.
Formula: Q= It Q:charge I:current , t:time(s)
1 Faraday= 96500 c/mol
Faraday's second law
Definition: the amount in mol, of electron needed to discharge 1 mol of an ion at an electrode is equal to the charge on the ion ,z.
example of electrolysis of aqueous solution.
type of electrode
Active copper electrodes.
Cathode: copper reduced.
Anode: copper oxidised.
innert graphite electrode.
CuSO4 ; Cu2+ and H2O to cathode, SO42- and H2O to anode.
Cu2+ discharged to cathode and
H2O discharged to anode. (SO42- not discharged)
electrolysis on water
dilute sulphuric acid
Cathode: H+, Anode: SO42- and H2O .
Cathode: H+ discharged and
Anode: H20 discharged (SO42- do not tend to oxidize
concentration of aqueous solution
Cathode: water will reduced. Anode: chloride ion will oxidised.
cathode: water will be reduced
Anode: water will be oxidised.
Factors affecting products of electrolysis.
Standard cell potential.
higher concentration: easily discharged ( halide ion)
Type of electrode.
involve in the process
do not involve.
non spontaneous reaction
happen in electrolytic cell
Electrical to chemical energy
electrolyte(free moving ion)