Electrolysis: JAMB Chemistry Questions, Answers & Notes

What Electrolysis covers in the JAMB Chemistry syllabus

Electrolysis decomposes an electrolyte (a molten or aqueous ionic substance) using an electric current. The anode is positive and the cathode negative; cations migrate to the cathode (where they are reduced — gain electrons) and anions to the anode (where they are oxidised — lose electrons). Faraday's first law: mass discharged ∝ charge, Q = It (coulombs); one mole of electrons carries ~96500 C (the Faraday). Inert electrodes (platinum, carbon) don't react; active ones do. Electrolysis is used for electroplating and to extract very reactive metals such as aluminium and sodium.

For Electrolysis, JAMB expects you to be able to:

• Explain electrolysis, electrolytes, electrodes, cations and anions
• Apply Faraday's laws (Q = It, the Faraday constant) and electrode reactions
• State applications such as electroplating and metal extraction

Key facts & revision notes: Electrolysis

These are the recurring points our Electrolysis questions test — revise them until each feels automatic, then practise the questions above to lock them in.

• Electrolysis decomposes an electrolyte using an electric current.
• An electrolyte conducts electricity (in molten/aqueous state) and is decomposed by it.
• The anode is the positive electrode; the cathode is negative.
• Cations are attracted to the negatively charged cathode.
• Anions are attracted to the positively charged anode.
• Hydrogen is liberated at the cathode during electrolysis of acidified water.
• Oxygen is liberated at the anode during electrolysis of acidified water.
• Faraday's first law: mass discharged ∝ charge passed (Q = It).
• Charge Q = current × time = It (coulombs).
• One mole of electrons carries about 96500 C — the Faraday constant.
• Electroplating deposits a metal coating using electrolysis.
• Q = It = 2 × (5 × 60) = 2 × 300 = 600 C.
• dilute H₂SO₄) provides ions so water can be electrolysed.
• Na⁺ ions are reduced to sodium metal at the cathode.
• Very reactive metals like aluminium and sodium are extracted by electrolysis.
• An active electrode participates in the reaction; an inert electrode (e.g.
• platinum, carbon) does not.
• Platinum (like carbon) is inert — it does not react during electrolysis.
• Electrolysis converts electrical energy into chemical energy (driving a non-spontaneous change).
• At the cathode, cations gain electrons — they are reduced.
• At the anode, anions lose electrons — they are oxidised.
• Anions lose electrons (are oxidised) at the anode.
• The copper anode dissolves, losing mass.
• Cu²⁺ ions gain electrons and deposit on the cathode.

Worked examples

Three Electrolysis questions with the answer and a short explanation, so you can see how the topic is set before you practise the full set.

How Electrolysis is tested in JAMB Chemistry

Our Electrolysis bank holds 40 questions (2 easy, 23 medium, 15 hard). JAMB Chemistry typically returns to Electrolysis year after year, so steady practice on this topic is high-value revision. Questions are multiple-choice with four options, and at UTME pace you get roughly 40 seconds each — which is why timed practice matters.

How to answer Electrolysis questions

Work the stem first and predict the answer before you look at the options; then eliminate the ones that contradict the key facts above. Watch for “which is not…”, “all of the above” and “except” style stems, which are where rushed candidates lose easy marks on Electrolysis. If a calculation or a precise definition is involved, work it from first principles rather than guessing from a half-remembered rule. When two options look right, re-read the stem for the qualifier that separates them — JAMB rarely repeats an option by accident. If you are still unsure, eliminate the two weakest choices to lift your odds, flag the question, and move on; never burn a full minute on one Chemistry item when the exam gives you about forty seconds each. Then come back to flagged questions with whatever time remains. The single most reliable way to get faster at Electrolysis is repeated timed practice, so use the button above until the recurring patterns feel automatic.

Common mistakes to avoid in Electrolysis

The errors that cost marks on Electrolysis are usually careless rather than conceptual: misreading a negative stem, confusing two similar terms, or rushing a definition you actually know. Candidates also over-rely on “expo” and last-minute cramming instead of understanding the topic — which fails the moment JAMB rephrases a familiar idea. Treat every option as a claim to be checked against the facts above, keep your working tidy for any calculation, and don’t change a considered answer on a hunch. Above all, revise Electrolysis actively by answering questions, not just by re-reading notes — recall under time is what the exam rewards.

Frequently asked questions

Is Electrolysis part of the JAMB Chemistry syllabus?

Yes. Electrolysis is a recognised topic in the JAMB Chemistry syllabus, covering explain electrolysis, electrolytes, electrodes, cations and anions. You should be able to recall its key facts and apply them to multiple-choice questions.

How many Electrolysis questions can I practise on Belmadeng?

There are 40 original, JAMB-standard Electrolysis questions in our free bank, each with the correct answer and a worked explanation. You can practise them untimed or as a timed test.

What are the most important points to know about Electrolysis?

Electrolysis decomposes an electrolyte (a molten or aqueous ionic substance) using an electric current. The anode is positive and the cathode negative; cations migrate to the cathode (where they are reduced — gain electrons) and anions to the anode (where they are oxidised — lose electrons). Faraday…

How do I answer Electrolysis questions quickly in JAMB?

Read the stem carefully, eliminate clearly wrong options, and match the remaining choices to the key facts for Electrolysis. Practising timed Electrolysis questions builds the speed you need for UTME's pace of about 40 seconds per question.

Are these JAMB Chemistry Electrolysis questions past questions or original?

They are original questions written to JAMB (UTME) standard and mapped to the official syllabus — not reproduced past papers. This keeps them legal to use freely while closely mirroring how the real exam tests the topic.

Where can I practise Electrolysis questions free without signing up?

Right here — tap “Start Electrolysis practice” on this page to begin instantly. Belmadeng's CBT practice is completely free and needs no sign-up, download or subscription.

About these questions: original, JAMB-standard items written from the official UTME Chemistry syllabus (last reviewed 2026-09-18). Belmadeng is an independent study platform and is not affiliated with JAMB. Spotted an error? Use the report link.