Cliffs AP Chemistry, 3rd Edition

7. Given the following diagram, determine which of the following statements is FALSE.

A. The solid zinc electrode is being reduced to Zn2+(aq).

B. The nickel electrode is the cathode.

C. The zinc electrode is the anode.

D. The nickel(II) ions are being reduced.

E. The Zn electrode will be negative in charge.

Answer: A

There are two types of cells: electrolytic (which requires a battery or external power source)
and voltaic (which requires no battery or external power source). The reaction in the diagram is
voltaic and therefore spontaneous. In a voltaic cell, the anode is the negative terminal, and oxi-
dation occurs at the anode. Remember the OIL portion of OIL RIG (Oxidation Is Losing elec-
trons) and AN OX (ANode is where OXidation occurs).

Zn(s) →Zn2+(aq) + 2 e–

The cathode is the positive terminal in a voltaic cell, and reduction occurs at the cathode.
Remember the RIG portion of OIL RIG (Reduction Is Gaining electrons) and RED CAT
(REDuction occurs at the CAThode).

Ni2+(aq) + 2 e–→Ni(s)

Na+ NO 3 –

Ni Ni+ Zn2+Zn

Ni2+(aq)+Zn(s) Ni(s)(+Zn2+aq)

NO 3 – NO 3 +

Part II: Specific Topics