QCEVault

Chemical synthesis — Question 23

QCAA 2023, Paper 1 · 6 marks

Q23 · 2023 · Paper 1Unclassified6 marks

QUESTION 23 (6 marks)

The diagram represents a hydrogen fuel cell with an acid electrolyte.

Anode (−)

Proton exchange membrane

Cathode (+)

Chemistry question figure

H2(g)

O2(g)

(a) Determine the redox half-equation occurring at the anode and cathode.

[2 marks]

Anode half-equation:

Cathode half-equation:

(b) Identify product Z.

[1 mark]

(c) Compare the movement of electrons and hydrogen ions in the fuel cell.

[3 marks]

Similarity:

Difference:

Significance:

Question linkQCAA assessment resources

Related questions

  1. Q11 · 2025 QCAA · Paper 1 · 1 mark
    QUESTION 11 Yeasts are used in the production of ethanol by fermentation to (A) increase the rate of the reaction. (B) act as a reactant in the overall reaction. (C) increase the yield of ethanol and ensure its purity. (D) produce green ethanol by preventing the production of carbon dioxide.
    Chemical synthesis
  2. Q26 · 2025 QCAA · Paper 1 · 3 marks
    QUESTION 26  (3 marks) One step of the contact process involves reacting sulfur dioxide (SO2) and oxygen (O2) to produce sulfur trioxide (SO3), as shown. 2SO2(g) + O2(g)  2SO3(g) The equilibrium constant (Kc) for the forward reaction is 5.6 × 104 at 350 °C and 9.2 × 101 at 800 °C. a) Determine whether the forward reaction is exothermic or endothermic. [1…
    Chemical synthesis
  3. Q29 · 2025 QCAA · Paper 1 · 6 marks
    QUESTION 29  (6 marks) The oxidation of meso-hydrobenzoin (C14H14O2) to produce benzaldehyde (C7H6O) was carried out via three different reaction pathways to evaluate atom economy and E-factor. Atom economy is a measure of reaction efficiency based on the percentage of the total mass of reactants successfully converted to the desired product. E-factor is a m…
    Chemical synthesis
  4. Q7 · 2025 QCAA · Paper 2 · 4 marks
    QUESTION 7  (4 marks) Contrast the operation of a hydrogen fuel cell under acidic conditions and a hydrogen fuel cell under alkaline conditions by completing the table. Hydrogen fuel cell Contrast Acidic conditions Alkaline conditions Electrolyte used Movement of ions Note: If you make a mistake, cancel it by ruling a single diagonal line through your work a…
    Chemical synthesis