Identify the location of oxidation in an electrochemical cell: the cathode the electrode the anode the salt bridge
The Correct Answer and Explanation is:
Correct Answer: The anode
Explanation:
In an electrochemical cell, oxidation always takes place at the anode, while reduction occurs at the cathode. This rule applies to both galvanic (voltaic) cells, which generate electrical energy from spontaneous chemical reactions, and electrolytic cells, which use electrical energy to drive non-spontaneous reactions.
Oxidation is the process in which a substance loses electrons. In an electrochemical cell, electrons produced at the anode travel through an external circuit toward the cathode. This flow of electrons is what generates the electrical current.
In a galvanic cell, the anode is typically marked as negative because electrons are released there due to oxidation. In contrast, the cathode is positive because it attracts electrons for the reduction reaction. However, in an electrolytic cell, the anode is considered positive and the cathode negative due to the direction of electron flow being forced by an external power source. Despite these differences in electrical charge labels, the location of oxidation at the anode remains consistent in both types of cells.
The salt bridge in an electrochemical cell does not participate directly in oxidation or reduction reactions. Instead, it serves to maintain electrical neutrality by allowing the movement of ions between the two half-cells. Without the salt bridge, the buildup of positive and negative charges would eventually stop the electron flow.
To summarize:
- Anode: site of oxidation (loss of electrons)
- Cathode: site of reduction (gain of electrons)
- Salt bridge: maintains ion balance between half-cells
- Electrode: general term for both anode and cathode, so it does not specify oxidation alone
Thus, oxidation specifically occurs at the anode, making it the correct answer.
