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CHAPTER 6 • 6 MARKS

Electricity and Chemical Reactions

Study electrolytes, electrolysis, electrode reactions, electroplating and practical applications of electrochemistry.

Topics in this chapter

  1. Conductors and electrolytes
  2. Strong and weak electrolytes
  3. Electrolysis
  4. Anode and cathode reactions
  5. Electrolysis of acidified water
  6. Electrolysis of copper sulphate
  7. Electroplating
  8. Industrial applications

Key learning points

✓ Electrolytes conduct through movement of ions.

✓ Oxidation occurs at the anode and reduction at the cathode.

✓ Electrolysis converts electrical energy into chemical change.

✓ Electroplating improves appearance and corrosion resistance.

Important equations and relations

Cathode: 2H⁺ + 2e⁻ → H₂Anode: 4OH⁻ → O₂ + 2H₂O + 4e⁻Cu²⁺ + 2e⁻ → CuCu → Cu²⁺ + 2e⁻

Multiple-choice questions

1. Reduction occurs at the:
  1. Anode
  2. Cathode
  3. Salt bridge
  4. Wire only

Answer: B — Cathode

2. The conducting particles in an electrolyte are:
  1. Ions
  2. Neutrons
  3. Photons
  4. Only atoms

Answer: A — Ions

3. Electroplating is an application of:
  1. Distillation
  2. Electrolysis
  3. Sublimation
  4. Filtration

Answer: B — Electrolysis

Very short-answer questions

  1. Define electrolysis.
  2. Which electrode is connected to the positive terminal in an electrolytic cell?
  3. Name one use of electroplating.

Short-answer questions

  1. Explain electrolysis of acidified water.
  2. Differentiate between metallic and electrolytic conduction.

Long-answer question

  1. Describe electrolysis of copper sulphate solution using copper electrodes and state its applications.