electrolysis - extras

Question 1

voltaic cell

Answer 1

a spontaneous redox reaction that is used to produe an electric current

Question 2

electrolytic cells

Answer 2

an electric current is used to drive a non-spontaneous reaction.

Question 3

How does reactivty of the ions effect what is prodused at the cathode = when an aqueos solution of Nacl is used

Answer 3

• more reactive ions are less likely to be reduced at the cathode and become their elemental form, becuase they are more stable in the ionic form. (Na+ more stable than Na)
• so instead of Na+, H+ ions ill be formed as they are less reactive than Na+ ions.

Question 4

How does reactivty of the ions effect what is prodused at the anode = when an aqueos solution of Nacl is used

Answer 4

here the more reactive ion will get oxidesed at the anode, as Cl2 is more stable than Cl-
compared to the OH- getting oxidised and forming water.

Question 5

what is formed at the anode in an aqueous solution of NaSO4

Answer 5

SO4^2- ions are very stable, so instead water is oxidised as less energy is needed to oxidise it (lower oxidation potential)
- so oxygen is formed at the anode.
2H2O → O2(g)+ 4H^+ +4e−

Question 6

whats produced at the cathode of an aqueous solution of AgNO3

Answer 6

Ag+ is reduced to form Ag
(instead of H+ cos Ag+ is less reactive than H+)

Question 7

cathode

Answer 7

the negative electrode

Question 8

anode

Answer 8

the positive electrode

Question 9

State the reactivity series

Answer 9

potassium
sodium
calcium
magnesium
aluminium
carbon
zinc
iron
tin
lead
hydrogen
copper
silver
gold
platinum.