SC10b Products from Electrolysis Flashcards
how can predict the electrolysis products of any molten, binary ionic compound?
the compound will always decompose into its elements
where is the metal and non metal produced in electrolysis?
metal is produced at the cathode and the non-metal is produced at the anode
When molten lead bromide is electrolysed, what is produced at the anode?
What is produced at the cathode?
anode - bromine
cathode - lead
what type of electrodes are used during electrolysis of molten or dissolved ionic salts?
inert
what are the inert electrodes usually made of?
platinum or graphite
what happens to the ions when a molten salt is electrolysed?
they are discharged as atoms or molecules at the electrodes
write a half equation for lead bromide.
Cathode Reaction:
Pb²+(l) + 2e- -> Pb
Anode Reaction:
2Br- -> Br2 + 2e-
how are solutions made?
dissolving a compound in water
electrolysis of copper chloride
products (tests) + half equations
cathode
~Copper is formed (Pink solid)
~Cu2+(aq) + 2e- → Cu(s)
anode
~Chlorine is formed (Bubbles. Turns damp blue litmus paper red, then bleaches white)
~2Cl-(aq) → Cl2(g) + 2e-
electrolysis of sodium chloride
product (tests) + half equations
cathode
~Hydrogen is formed (Bubbles. Lit splint. Squeaky pop)
~2H+(aq) + 2e- → H2(g)
anode
~Chlorine is formed (Bubbles. Turns damp blue litmus paper red, then bleaches white)
~2Cl-(aq) → Cl2(g) + 2e-
electrolysis of sodium sulfate
product (tests) + half equations
cathode
~Hydrogen is formed (Bubbles. Lit splint. Squeaky pop)
~2H+(aq) + 2e- → H2(g)
anode
~Oxygen is formed (Bubbles. Glowing splint burns brighter)
~2O2-(aq) → O2(g) + 4e-
electrolysis of acidified water
products (tests) + half equations
cathode
~Hydrogen is formed (Bubbles. Lit splint. Squeaky pop)
~2H+(aq) + 2e- → H2(g)
anode
~Oxygen is formed (Bubbles. Glowing splint burns brighter)
~2O2-(aq) → O2(g) + 4e-
what does water decompose into?
hydrogen and oxygen
The electrolysis of sodium chloride solution does not produce sodium metal.
State how you would change the electrolyte to obtain metallic sodium (1 mark)
use molten sodium chloride
10.4 Explain the formation of the products in the electrolysis of a variety of common compounds and solution (copper chloride solution, sodium chloride solution, sodium sulfate solution, acidified water, molten lead bromide).
