5.4.3.5 Representation of Reactions at Electrodes as Half Equations Flashcards
1
Q
What happens at the cathode during electrolysis?
A
- positively charged ions gain electrons
- so reactions are reductions
2
Q
What happens at the anode during electrolysis?
A
- negatively charged ions lose electrons
- so reactions are oxidations
3
Q
How are reactions at electrodes represented?
A
- by half equations
4
Q
What are examples of half equations?
A
- 2H+ + 2e- → H2
and
4OH- → O2 + 2H2 O + 4e-
or - 4OH- – 4e- → O2 + 2H2 O
5
Q
How do you write a half equation at the cathode (negative)?
A
- X+ + e- → X
6
Q
How do you write a half equation at the anode (positive)?
A
- X- → e- +X
