Which one of the following statements about acidic propan-1-ol fuel cells is correct? A - VCE - SSCE Chemistry - Question 24 - 2023 - Paper 1

To assess which statement is correct, we evaluate each option:

A. Positive ions flow through the membrane to the cathode. This is true because, in fuel cells, protons (positive ions) migrate through the electrolyte towards the cathode, facilitating the electrochemical reaction.

B. The voltage decreases since the reactants are used up in the half-cell reactions. While reactants are indeed consumed during the reaction, the voltage typically does not decrease solely for this reason—it can also depend on several other factors, such as concentration and temperature.

C. H₂O is formed at the negative electrode and CO₂ is formed at the positive electrode. This statement is generally accurate in the context of acidic fuel cells where water is generated as a byproduct at the cathode.

D. Since it is a gas, O₂ is the only reactant that must have direct contact with the electrode. While O₂ does require contact with the electrode, this statement overlooks the role of other reagents in the process.

After reviewing all the options, the most correct answer is A.