Which one of the following reactions must be carried out in an electrolytic cell rather than in a galvanic cell?
◦ Zn2+(aq)+ Ca(s) → Zn(s) + Ca2+(aq)
◦ Al3+(aq) + 3Br–(aq) → Al(s) + (3/2)Br2(l)
◦ 2Al(s) + 3Fe2+(aq) → 2Al3+(aq) + 3Fe(s)
◦ H2(g) + I2(s) → 2H+(aq) + 2I–(aq)
◦ Fe2+(aq) + Mg(s) → Fe(s) + Mg2+(aq)