Chemical Equilibrium: JAMB Chemistry Questions, Answers & Notes

What Chemical Equilibrium covers in the JAMB Chemistry syllabus

A reversible reaction (shown by ⇌) can go both ways; in a closed system it reaches dynamic equilibrium, where the forward and backward rates are equal and concentrations stay constant. Le Chatelier's principle predicts the response to disturbance: the equilibrium shifts to oppose the change. Adding a reactant (or removing a product) shifts it toward products; increasing temperature favours the endothermic direction; increasing pressure favours the side with fewer gas molecules. A catalyst speeds up reaching equilibrium but does not shift its position. These ideas guide industrial processes like the Haber process (N₂ + 3H₂ ⇌ 2NH₃), which uses high pressure and a moderate temperature.

For Chemical Equilibrium, JAMB expects you to be able to:

• Explain reversible reactions and dynamic equilibrium
• Apply Le Chatelier's principle to concentration, temperature and pressure changes
• Relate equilibrium to industrial processes such as the Haber process

Key facts & revision notes: Chemical Equilibrium

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

• A reversible reaction can go both forward and backward.
• At equilibrium, the forward and backward reaction rates are equal.
• It is dynamic because both reactions continue, but at equal rates, so concentrations stay constant.
• Le Chatelier's principle: the equilibrium shifts to oppose (minimise) the imposed change.
• Adding reactant shifts the equilibrium toward the products to use it up.
• Adding heat to an exothermic reaction favours the endothermic (backward) direction, shifting left.
• Higher pressure favours the side with fewer gas molecules, reducing the pressure.
• At equilibrium, concentrations remain constant (though not necessarily equal).
• A catalyst speeds up attainment of equilibrium equally both ways; it does not shift the position.
• The Haber process (N₂ + 3H₂ ⇌ 2NH₃) is a classic reversible, equilibrium reaction.
• Removing product makes the system shift right to replace it (Le Chatelier's principle).
• N₂ + 3H₂ → 2NH₃ goes from 4 to 2 gas molecules, so high pressure favours ammonia.
• The double arrow ⇌ shows a reversible reaction that can reach equilibrium.
• A catalyst speeds both directions equally, so it does not shift the equilibrium position.
• Heat favours the endothermic direction, so raising temperature shifts an endothermic reaction forward.
• A true equilibrium requires a closed system so no substances escape.
• If both sides have equal gas moles, pressure change does not shift the equilibrium.
• At equilibrium, observable (macroscopic) properties stay constant.
• High pressure (fewer molecules) and a moderate temperature give a good ammonia yield in reasonable time.
• An irreversible reaction proceeds essentially fully in one direction.
• Lower pressure favours the side with more moles of gas (4 on the left vs 2 on the right).
• The equilibrium shifts right to use up the added reactant.
• Cooling favours the exothermic (forward) direction, making more product.
• Cooling opposes the heat-absorbing forward reaction, favouring reactants.

Worked examples

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

How Chemical Equilibrium is tested in JAMB Chemistry

Our Chemical Equilibrium bank holds 40 questions (3 easy, 16 medium, 21 hard). JAMB Chemistry typically returns to Chemical Equilibrium 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 Chemical Equilibrium 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 Chemical Equilibrium. 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 Chemical Equilibrium is repeated timed practice, so use the button above until the recurring patterns feel automatic.

Common mistakes to avoid in Chemical Equilibrium

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

Frequently asked questions

Is Chemical Equilibrium part of the JAMB Chemistry syllabus?

Yes. Chemical Equilibrium is a recognised topic in the JAMB Chemistry syllabus, covering explain reversible reactions and dynamic equilibrium. You should be able to recall its key facts and apply them to multiple-choice questions.

How many Chemical Equilibrium questions can I practise on Belmadeng?

There are 40 original, JAMB-standard Chemical Equilibrium 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 Chemical Equilibrium?

A reversible reaction (shown by ⇌) can go both ways; in a closed system it reaches dynamic equilibrium, where the forward and backward rates are equal and concentrations stay constant. Le Chatelier's principle predicts the response to disturbance: the equilibrium shifts to oppose the change. Adding …

How do I answer Chemical Equilibrium questions quickly in JAMB?

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

Are these JAMB Chemistry Chemical Equilibrium 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 Chemical Equilibrium questions free without signing up?

Right here — tap “Start Chemical Equilibrium 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.