Oxygen and Hydrogen
Explanation
The chemical effect of electric current, specifically the electrolysis of water. In 1800, William Nicholson demonstrated that passing an electric current through acidified water decomposes it into its constituent elements, hydrogen and oxygen.
Detailed Analysis:
- Electrode Polarity: In an electrolytic cell, the electrode connected to the positive terminal of the battery is called the Anode, and the electrode connected to the negative terminal is called the Cathode.
- Reaction at the Anode (Positive Electrode): Oxidation occurs at the positive terminal. Oxygen-containing species lose electrons, leading to the evolution of Oxygen gas bubbles.
- Reaction at the Cathode (Negative Electrode): Reduction occurs at the negative terminal. Hydrogen ions gain electrons, leading to the evolution of Hydrogen gas bubbles.
Key Takeaway:
During the electrolysis of water, Oxygen is evolved at the Anode (Positive) and Hydrogen is evolved at the Cathode (Negative).