B. The diagram below shows a key being plated with copper in an electrolytic cell.
B
CuSO (aq)
Copper Battery
electrode
Given the reduction reaction for this cell:
Cu2+ (aq) + 2e - Cu(s)
This reduction occurs at
A A, which is the anode
® A, which is the cathode
CB, which is the anode
DB, which is the cathode

2h2o2--> 2h2o + o2

this reaction is of the spontaneous decomposition of hydrogen peroxide down into water and oxygen.

add 2 molecules of hydrogen peroxide and 2 molecules of water. since oxygen is naturally diatomic, the total number of atoms of each element is now the same on both sides of the equation so it is balanced.

this may not be entirely correct but let me know.