This exam tips covers Exam Tips for Electrolysis of Molten Compounds within Electrolysis of Molten Compounds for GCSE Chemistry. Revise Electrolysis of Molten Compounds in Electrolysis for GCSE Chemistry with 21 exam-style questions and 14 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 10 of 11 in this topic. Treat this as a marking guide for what examiners are looking for, not just a fact list.
💡 Exam Tips for Electrolysis of Molten Compounds
🎯 Common Question Types:
- "Explain why the compound must be molten" (2 marks)
- "Predict the products at each electrode" (2 marks)
- "Write the half equation at the cathode/anode" (1-2 marks)
- "Identify which process is oxidation and which is reduction" (1 mark)
📝 Key Command Words:
- Explain — state the reason with detail (e.g., "ions are free to move" not just "it conducts")
- Predict — use the rules to state what will form and where
- Write a half equation — must include electrons and be balanced for charge and atoms
⚠️ Common Mistakes to Avoid:
- Saying "electricity flows through the electrolyte" — it is IONS, not electrons, that move inside
- Not balancing the charge in half equations (2Br⁻ → Br₂ + 2e⁻, not Br⁻ → Br + e⁻)
- Writing "Br" instead of "Br₂" — bromine is diatomic
- Confusing which electrode is positive and which is negative
Quick Check: At which electrode does oxidation occur during electrolysis, and what does this mean in terms of electrons?
Oxidation occurs at the anode (the positive electrode). Oxidation means loss of electrons — the anions that arrive at the anode give up their extra electrons to the electrode, becoming neutral atoms or molecules. Remember: OIL RIG — Oxidation Is Loss, Reduction Is Gain.
Practice questions for Electrolysis of Molten Compounds
Which condition is required for electrolysis to occur with an ionic compound?
State the products formed at each electrode when molten lead bromide (PbBr₂) is electrolysed.