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chemistry igcse acapprinted 32 · PDF 32
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C
D
Chlorine
Chlorine
Oxygen
Hydrogen
Q2. Which statement about hydrogen–oxygen fuel cells is correct?
Hydrogen is extracted from clean, dry air.
The only product is carbon dioxide.
The reaction is endothermic.
No toxic gasses are produced.
Q3. Which statement about electrolysis is correct?
Chemical energy is converted to electrical energy.
Electrons flow through the electrolyte.
Ionic compounds are broken down.
Metals are formed at the positive electrode.
Q4. A metal object is electroplated with copper. One electrode is the metal object and the other
electrode is copper. The electrolyte is aqueous copper(II) sulfate. Which row shows the ionic half-
equation for the reaction at the anode and the observation of the electrolyte?
Anode
Electrolyte
A
B
C
D
Cu2+ + 2e– → Cu
Cu2+ + 2e– → Cu
Cu → Cu2+ + 2e–
Cu → Cu2+ + 2e–
Blue colour fades
Blue colour does not change
Blue colour fades
Blue colour does not change
Q5. Aqueous copper(II) sulfate is electrolysed using copper electrodes. What is the half-equation
for the reaction at the cathode?
2H+ +2e– → H2
4OH– → O2 + 2H2O + 4e–