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Electrode potentials and electrochemical cells (A-level only)

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Question 19

This question is about a direct ethanol–oxygen fuel cell operating under acidic conditions. When the cell operates, ethanol (C2H5OH\text{C}_2\text{H}_5\text{OH}C2​H5​OH) molecules react with water at the negative electrode to form carbon dioxide and hydrogen ions. Oxygen gas reacts with hydrogen ions to form water at the positive electrode.

a.

Deduce the half-equation for the reaction at the negative electrode.

[1]
b.

Deduce the half-equation for the reaction at the positive electrode.

[1]
c.

Give the equation for the overall reaction that occurs in this ethanol–oxygen fuel cell.

[1]
d.

The negative electrode is made of a platinum–ruthenium alloy (Pt-Ru\text{Pt-Ru}Pt-Ru) and the positive electrode is made of platinum (Pt\text{Pt}Pt). Give the conventional representation for this fuel cell.

[2]
e.

State what must be done to maintain the EMF of this fuel cell when in use.

[1]

Electrode potentials and electrochemical cells (A-level only) Questions

  1. A Level
  2. /Chemistry
  3. /Electrode potentials and electrochemical cells (A-level only)