Which observation is typical of electrolysis of an aqueous solution?

• A. Fizz of gases produced
• B. No visible change
• C. The solution solidifies
• D. The color of solution changes randomly

Answer: (A)

When an electric current passes through an aqueous solution, ions move to the electrodes and water can be split to form gases. This gas evolution creates bubbles at the electrodes, so you see fizzing. Hydrogen gas appears at the cathode and oxygen at the anode, giving a visible sign that electrolysis is occurring. The other possibilities—no visible change, the solution solidifying, or random color changes—don’t match what typically happens during electrolysis of a water-based solution.