Cell notation, electrolytic cells and electrolysis

Cell notation, electrolytic cells and electrolysis

Cell notation represents a galvanic cell compactly: anode material | anode ions || cathode ions | cathode material, with the double line indicating a salt bridge or porous separator. It should match the oxidation-left, reduction-right convention in typical cell notation. Electrolytic cells use an external power supply to drive non-spontaneous redox reactions; oxidation is still at the anode and reduction still at the cathode, but electrode signs reverse relative to a galvanic cell. Electrolysis questions require identifying which ions can be discharged, writing half-reactions and checking charge and atom balance. Do not assume ions simply travel to an electrode without considering reduction or oxidation feasibility.

Work it through

For a zinc-copper galvanic cell, Zn(s)|Zn²⁺(aq)||Cu²⁺(aq)|Cu(s) shows zinc oxidation on the left and copper reduction on the right. In an electrolytic cell, a battery pushes electrons to the cathode, where reduction occurs. Labels must state the cell type before assigning positive or negative electrode signs.

Mastery target

Read or construct basic cell notation, distinguish galvanic from electrolytic operation and use invariant redox definitions to assign anode and cathode.