Dse Chemistry Past Paper By Topic -

| Q Year | Sub-topic | Mistake type | Correct concept | Action | | :--- | :--- | :--- | :--- | :--- | | 2018 Q9 | Metal reactivity series | Wrong order of displacement | More reactive metal displaces less reactive | Memorize series + test yourself | | 2022 Q12c | Electrolysis of CuSO₄ | Anode reaction wrong | OH⁻ oxidized to O₂, not Cu | Redo anode/cathode rule table |

| Topic | Weight (Paper 1) | Difficulty | Common Question Types | | :--- | :--- | :--- | :--- | | Redox & Electrochemistry | 15–18% | ⭐⭐⭐⭐ | Chemical cell vs electrolytic cell, half equations, rusting prevention | | Molarity & Mole Calculation | 12–15% | ⭐⭐⭐ | Titration calculation, limiting reagent, % by mass | | Organic Chemistry (I & II) | 18–20% | ⭐⭐⭐⭐ | IUPAC naming, reaction pathways, polymer structure | | Rate of Reaction | 8–10% | ⭐⭐⭐ | Graph slope, Maxwell-Boltzmann, catalyst experiments | | Equilibrium | 6–8% | ⭐⭐⭐⭐⭐ | Le Chatelier, Kc calculation (rarely Kp), concentration-time graphs | | Acids & Bases | 10–12% | ⭐⭐⭐ | pH, strong/weak, salt hydrolysis, titration curves | dse chemistry past paper by topic

❌ – Repeating same mistake across topics = wasted time. | Q Year | Sub-topic | Mistake type