Qualitative Analysis & Organic Workflow for H2 Chemistry Paper 4

Q: What does Qualitative Analysis & Organic Workflow for H2 Chemistry Paper 4 cover?
A: A structured workflow for inorganic qualitative analysis and small-scale organic tasks—covering planning scripts, observation logging, and ACE commentary aligned with MOE’s 2025 practical expectations.

TL;DR
Paper 4 still leans on qualitative analysis (QA) and organic workups. MOE supplies QA notes during the exam, but you must plan reagent sequences, manage heating safely, and phrase observations precisely.
Use decision trees, log colours/precipitates accurately, capture confirmatory tests, and evaluate contamination or reagent freshness in ACE write-ups.

1 | QA and organic tasks in Paper 4

• The MOE 2025 Pre-University Chemistry syllabus highlights qualitative inorganic analysis (cations/anions, gas tests) and organic procedures (reflux, distillation, qualitative tests) as recurring Paper 4 contexts.
• Paper 4 lasts 2 h 30 min, carries 50 marks, and is weighted at 20 % of the H2 grade; Planning accounts for 4 %, while MMO, PDO, ACE share the remaining 16 %.
• Qualitative Analysis notes are provided, but candidates must choose the correct reagents, order of tests, and safety precautions without prompting.

2 | Planning scripts that score

Structure planning responses around:

• Aim and identity hypotheses — e.g., “Identify cations in sample A; suspected Group II ion based on context.”
• Test sequence — state preliminary checks (flame test, carbonate test), followed by confirmatory reagents (NH₃(aq), NaOH(aq), anion tests). Justify order to minimise cross-contamination.
• Volumes and apparatus — indicate droplet counts, heating method (water bath, sand bath), and glassware.
• Safety — note ventilation (fume hood for concentrated acids, bromine water), PPE, and waste containers for heavy-metal precipitates.
• Organic tasks — mention reflux duration, condenser cooling, solvent choice for recrystallisation, and how fractions will be collected/distilled.
• Data usage — explain how observations link to inference tables in the supplied QA notes or how melting point/TLC will confirm organic purity.

3 | MMO routines for reliable observations