A voltaic cell is constructed in which the following cell reaction occurs. The half-cell compartments are connected by a salt bridge. 3Fe^3+ (aq) + Al(s) rightarrow 3Fe^2+ (aq) + Al^3+ (aq) The anode reaction is: The cathode reaction is: In the external circuit, electrons migrate the Fe^2+|Fe^3+ electrode the Al|Al^3+ electrode. In the salt bridge, anions migrate the Al|Al^3+ compartment the Fe^2+|Fe^3+ compartment.