Consider an electrochemical cell constructed from the following half cells, link
ID: 834808 • Letter: C
Question
Consider an electrochemical cell constructed from the following half cells, linked by a KCl salt bridge.
- an Al(s) electrode in 0.5 M Al2(SO4)3 solution
- a Pb(s) electrode in 1.0 M Pb(NO3)2 solution
Which electrode is the anode?
A)
Al
B)
Pb
C)
Neither
Consider an electrochemical cell constructed from the following half cells, linked by a KCl salt bridge.
- an Al(s) electrode in 0.5 M Al2(SO4)3 solution
- a Pb(s) electrode in 1.0 M Pb(NO3)2 solution
Which electrode is the anode?
A)
Al
B)
Pb
C)
Neither
Explanation / Answer
Al
this is because the standard reduction potential for Al is more negative than that of Pb. The anode is oxidized and the cathode is reduced. the standard reduction potential of the cell has to be the most positive value, so Al has to be the one being oxidized (the oxidation potential is the same as the reduction potential, but the sign is reversed. So since the reduction potential of Al is negative, the oxidation potential is positive. The reduction potential of the cell is equal to the sum of the oxidation potential of the oxidized substance and the reduction potential of the substance being reduced).