Solubility: JAMB Chemistry Questions, Answers & Notes

What Solubility covers in the JAMB Chemistry syllabus

A solution is a solute dissolved in a solvent (water is the 'universal solvent'). A saturated solution holds the maximum solute at that temperature; unsaturated holds less; supersaturated holds more and is unstable. Solubility is the mass of solute that saturates 100 g of solvent at a given temperature. For most solids, solubility rises with temperature (shown by a solubility curve), so cooling a hot saturated solution deposits crystals; for gases, solubility falls with temperature but rises with pressure (fizzy drinks). Dissolving is faster with stirring, heat and crushing. Fractional crystallisation separates solids by their differing solubilities.

For Solubility, JAMB expects you to be able to:

• Define solute, solvent, solution, and saturated/unsaturated/supersaturated
• Describe how temperature and pressure affect the solubility of solids and gases
• Interpret solubility curves and apply crystallisation

Key facts & revision notes: Solubility

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

• A solution is a solute dissolved in a solvent.
• The solute is the substance that dissolves (e.g.
• A saturated solution holds the maximum solute it can dissolve at that temperature.
• For most solids, solubility increases with rising temperature.
• Gas solubility decreases as temperature rises (warm drinks lose their fizz).
• A supersaturated solution holds more solute than a saturated one and is unstable.
• Solubility is quoted per 100 g of solvent at a stated temperature.
• A solubility curve plots solubility against temperature.
• Fats and oils dissolve in organic solvents (petrol, ether), not in water.
• Half the water dissolves half the mass: 40/2 = 20 g.
• Water dissolves so many substances that it is called the universal solvent.
• Higher pressure increases the solubility of a gas in a liquid (as in fizzy drinks).
• Cooling a hot saturated solution causes the excess solute to crystallise out.
• An insoluble substance does not dissolve in the given solvent.
• Stirring, warming and increasing surface area (crushing) speed up dissolving.
• water and ethanol) mix in all proportions.
• Crystals deposited = 60 − 20 = 40 g per 100 g of water.
• Calcium carbonate (chalk/limestone) is insoluble in water; the others dissolve readily.
• A dilute solution has a small amount of solute relative to the solvent.
• Fractional crystallisation exploits differing solubilities to separate two dissolved solids.
• The solvent is the dissolving medium.
• An unsaturated solution has not yet reached its limit.
• It is called a solubility curve.
• Gas solubility falls with rising temperature, so the gas escapes.

Worked examples

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

How Solubility is tested in JAMB Chemistry

Our Solubility bank holds 40 questions (9 easy, 20 medium, 11 hard). JAMB Chemistry typically returns to Solubility 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 Solubility 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 Solubility. 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 Solubility is repeated timed practice, so use the button above until the recurring patterns feel automatic.

Common mistakes to avoid in Solubility

The errors that cost marks on Solubility 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 Solubility actively by answering questions, not just by re-reading notes — recall under time is what the exam rewards.

Frequently asked questions

Is Solubility part of the JAMB Chemistry syllabus?

Yes. Solubility is a recognised topic in the JAMB Chemistry syllabus, covering define solute, solvent, solution, and saturated/unsaturated/supersaturated. You should be able to recall its key facts and apply them to multiple-choice questions.

How many Solubility questions can I practise on Belmadeng?

There are 40 original, JAMB-standard Solubility 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 Solubility?

A solution is a solute dissolved in a solvent (water is the 'universal solvent'). A saturated solution holds the maximum solute at that temperature; unsaturated holds less; supersaturated holds more and is unstable. Solubility is the mass of solute that saturates 100 g of solvent at a given temperat…

How do I answer Solubility questions quickly in JAMB?

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

Are these JAMB Chemistry Solubility 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 Solubility questions free without signing up?

Right here — tap “Start Solubility 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.