Updated November 2026. These KCSE 2026 Chemistry Paper 1 (233/1) predicted questions are built from past-paper trends: we ranked the topics that past KCSE Chemistry Paper 1 papers test most often, then wrote original practice questions on them. They are not leaked, official or guaranteed questions, and this site is not linked to KNEC or KICD. Use them to practise the areas most likely to appear, alongside your full syllabus revision.
KCSE Chemistry 233/1 prediction: most commonly tested topics
The ranking below comes from the topic coverage of past KCSE papers, as summarised in our paper guides. It is a ranking, not an exact count: exam papers change every year.
| Rank | Topic | How it is usually tested |
|---|---|---|
| 1 | Atomic structure and the periodic table | Electron arrangement, trends in groups and periods |
| 2 | Chemical bonding | Ionic, covalent, dative and metallic bonds; dot-and-cross diagrams |
| 3 | Acids, bases and salts | pH, preparation of salts, solubility |
| 4 | Gas preparation and tests | Oxygen, hydrogen, carbon(IV) oxide, ammonia, chlorine |
| 5 | Separation methods | Chromatography, fractional distillation, sublimation |
| 6 | Nitrogen and its compounds | Haber process, nitric(V) acid, ammonium salts |
| 7 | Sulphur and its compounds | Contact process, sulphuric(VI) acid properties |
| 8 | Hardness of water | Temporary and permanent hardness and how to remove them |
Free sample: 3 KCSE 2026 Chemistry Paper 1 predicted questions
Q1. Element X has atomic number 17. Write its electron arrangement and state its group and period.
Marking scheme
2.8.7. Group VII, period 3.
Q2. Explain why the melting point of sodium chloride is much higher than that of hydrogen chloride.
Marking scheme
Sodium chloride has a giant ionic structure with strong electrostatic forces between ions in all directions. Hydrogen chloride is made of simple molecules held by weak van der Waals forces, which need little energy to break.
Q3. State the conditions used in the Haber process.
Marking scheme
Temperature about 450–500°C, pressure about 200–250 atm, a finely divided iron catalyst, and nitrogen and hydrogen in a 1:3 ratio.
Full set: 16 more predicted questions with marking scheme
16 more predicted questions with full marking schemes are locked. They cover every topic in the table above.
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Frequently asked questions
Are these the real KCSE 2026 Chemistry Paper 1 questions?
No. Nobody outside KNEC knows the real questions, and any site claiming a leak is lying or breaking the law. These are original practice questions written by the CBC Guide team, predicted from the topics past KCSE papers test most often.
Which topics come up most in KCSE Chemistry Paper 1 (233/1)?
The most commonly tested areas in past papers are Atomic structure and the periodic table, Chemical bonding, Acids, bases and salts, Gas preparation and tests. The full ranked list is in the table above.
How do I get the full set of predicted questions?
The first 3 questions are free. The remaining 16, each with a marking scheme, unlock with the KSh 20 Day Pass or the KSh 500 Monthly Pass, paid by M-Pesa. The passes do not auto-renew.
How should I use predicted questions in the last days before the exam?
Answer each question under time, mark it with the scheme, then go back to your notes for any topic you got wrong. Do not skip topics that are not on this list, because KNEC can test any part of the syllabus.
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