Final answer:
To ensure no oxygen gas is formed at the anode during water electrolysis, collect the gas in a tube and use a glowing splint test; the splint re-igniting indicates oxygen presence.
Step-by-step explanation:
To confirm that no oxygen gas is given off at the anode during the electrolysis of water, one could perform a simple experiment. Set up the apparatus with two pencil tips as electrodes submerged in an electrolyte solution such as diluted sulfuric acid. When you pass an electric current through the electrolyte, oxygen will form at the anode and hydrogen at the cathode. To confirm the presence of oxygen, you can collect the gas released at the anode in an inverted test tube and perform a glowing splint test. The splint will re-ignite in the presence of oxygen, confirming its production. This is because electrolysis of water involves the oxidation of water at the anode to produce oxygen gas and hydrogen ions, while the cathode sees the reduction of water to hydrogen gas and hydroxide ions.