Which of the following statements about an electrochemical cell is correct? Oxidation occurs

Step 1: Analyze the question You are asked where oxidation takes place in an electrochemical cell.

Step 2: Explain the concept Oxidation is the loss of electrons. Reduction is the gain of electrons.

A handy memory aid is OIL RIG (Oxidation Is Loss, Reduction Is Gain). Another is AN OX, RED CAT: ANode = OXidation, REDuction = CAThode.

In any electrochemical cell (galvanic or electrolytic):

• Anode: the electrode where oxidation occurs. Electrons leave the species here.
• Cathode: the electrode where reduction occurs. Electrons are gained here.
• Salt bridge: it only allows ions to move so the solutions stay electrically neutral and the circuit is complete. No redox reaction happens in it.
• Aqueous solution (electrolyte): it carries ions, but the electron transfer (oxidation and reduction) takes place at the electrode surfaces.

Step 3: Check each option

• A. At the anode: Correct. Oxidation (loss of electrons) happens at the anode.
• B. At the cathode: Wrong. Reduction happens at the cathode.
• C. Through the salt bridge: Wrong. Ions migrate through it, and no oxidation occurs there.
• D. In the aqueous solution: Wrong. The electrolyte conducts ions but is not the site of the electrode half-reactions.

Example (Daniell cell): At the zinc anode: Zn(s) → Zn²⁺(aq) + 2e⁻ (oxidation) At the copper cathode: Cu²⁺(aq) + 2e⁻ → Cu(s) (reduction)

Step 4: Answer Oxidation occurs at the anode, which is option A.

Exam tip: Remember "AN OX" (Anode = Oxidation) and "RED CAT" (Reduction = Cathode). The vowels and consonants match: Anode and Oxidation both begin with vowels, while Cathode and Reduction both begin with consonants.