Electrolysis Setup: Anode and Cathode
Identify electrodes, ions, and electron flow direction.
What this lesson covers
Why it matters
Connect a battery to two electrodes dipped in molten salt. Watch the invisible ions rush to opposite ends, driven by an electric current.
Predict first
In an electrolytic cell, which direction do the positive ions (cations) move?
Opposites attract: cations are positive, so they are drawn to the negative cathode where they gain electrons.
- Towards the anode (positive electrode)
- Towards the cathode (negative electrode) — correct
- They stay in the middle of the solution
What you do
Build sodium — 11 protons, 12 neutrons and 11 electrons (mass number 23) — then strip one electron off. The Na⁺ you just made is the cation that swims to the cathode during electrolysis and collects its electron back.
Check yourself
What happens to a cation when it reaches the cathode?
Reduction is the gain of electrons. At the cathode, cations accept electrons to become neutral atoms.
Why is the anode considered the site of oxidation?
Oxidation is the loss of electrons. Anions migrate to the anode and release electrons, becoming neutral atoms or molecules.
- It loses electrons and becomes more positive
- It gains electrons and is reduced — correct
- It splits into neutral atoms without electron transfer
- Because anions lose electrons there — correct
- Because the anode is made of a reactive metal
- Because oxygen is always produced at the anode