Advanced Organic Synthesis & Purification Labs for H2 Chemistry Paper 4
Download printable cheat-sheet (CC-BY 4.0)17 Nov 2025, 00:00 Z
Want small-group support? Browse our A-Level Chemistry Tuition hub. Not sure which level to start with? Visit Chemistry Tuition Singapore.
Looking for the full lab practical series? Visit the H2 Chemistry Practicals.
Planning a revision session? Use our study places near me map to find libraries, community study rooms, and late-night spots.
Q: What does Advanced Organic Synthesis & Purification cover?
A: Step-by-step Paper 4 workflows for reflux, distillation, liquid–liquid extraction, recrystallisation, chromatography, and yield tracking-plus ACE commentary frameworks grounded in SEAB’s 2026 H2 Chemistry syllabus.
TL;DR
Organic tasks combine synthetic precision with safety discipline.
Control heating, phase separations, drying, and purity calculations so you can justify every observation and improvement during Paper 4.
Keep this workflow with the rest of your Paper 4 drills in our H2 Chemistry Experiments hub.
Status: SEAB H2 Chemistry (9729, first exam 2026) syllabus last checked 2025-11-29 (PDF last modified 2024-07-17). Paper 4 remains 2 h 30 min, 55 marks, weighted at 20 % with Planning at 5 % and MMO/PDO/ACE at 15 % combined; simple organic synthesis and purification stay listed in the practical scope.
1 | Organic investigations in the 2026 syllabus
- The SEAB 2026 H2 Chemistry syllabus (9729) lists simple organic synthesis and purification in the Practical Assessment section (Paper 4: 2 h 30 min, 55 marks; Planning 5%, MMO/PDO/ACE 15%). Candidates must demonstrate safe manipulation, accurate observation, and evaluative commentary.
- Examiner reports often flag incomplete purification, poor yield documentation, and missing safety controls (e.g., reflux set-ups lacking clamps or open joints).
- The 9476 Paper 4 specimen for 2026 backs this up-Question 2 walks through an organic preparation, TLC confirmation, and yield discussion, echoing the reflux, extraction, and purification checkpoints summarised here.
- Common Paper 4 scenarios: esterification under reflux, nitration, oxidation/reduction, separation of product from by-products, determination of purity via melting point or TLC.
2 | Reflux & distillation mastery
- Apparatus: round-bottom flask, anti-bumping granules, Liebig or Allihn condenser (water in at bottom/out at top), heating mantle/hot plate, drying tube (when excluding moisture).
- Reflux steps: charge reagents, add anti-bumping granules, clamp securely, start coolant before heating, maintain gentle boil (liquid should return without climbing condenser).
- Distillation: switch to a still head with thermometer adapter and receiving adapter; monitor temperature plateau to identify fraction.
- Troubleshooting:
