Class 10th notes

🧠 Memory Tricks for Class 10 Science 🔥 Physical vs Chemical Changes 1. Burning → Chemical (new substance + energy released) 2. Melting/Ice → Physical (no new substance, just state change) 3. Boiling water → Physical 4. Rusting iron → Chemical (new brown flaky substance) 5. Cutting vegetables → Physical 6. Cooking vegetables → Chemical (new taste, smell, can’t reverse) 7. Dissolving salt in water → Physical (can get salt back) 8. Dissolving milk powder in water → Physical 9. Fermentation of sugar → Chemical (alcohol forms, irreversible) 10. Photosynthesis → Chemical (new glucose + O₂ formed) 👉 Shortcut: If new substance is formed → Chemical. If only appearance changes → Physical. ⚗️ Acids, Bases & Salts 1. Acid + Metal → H₂ gas (remember: “Acid attacks Metal → Hydrogen flies”) Example: Zn + H₂SO₄ → ZnSO₄ + H₂↑ 2. Acid + Base → Salt + Water (Neutralization reaction 🌊) Example: HCl + NaOH → NaCl + H₂O 3. Carbonate + Acid → CO₂ gas (remember: “C-A → CO₂”) Example: Na₂CO₃ + HCl → NaCl + CO₂↑ + H₂O 4. Bases feel soapy, Acids taste sour (don’t taste in lab 😂 just remember lemon = acid, soap = base). 5. Litmus Test: Acid → Blue to Red Base → Red to Blue 🔄 Types of Chemical Reactions 1. Combination = Coming Together A + B → AB (Example: C + O₂ → CO₂) 2. Decomposition = Breaking AB → A + B (Heat/Light/Electricity used to break down) 3. Displacement = Strong pushes Weak A + BC → AC + B (Example: Zn + CuSO₄ → ZnSO₄ + Cu) 4. Double Displacement = Exchange of Partners 💍 AB + CD → AD + CB (Example: Na₂SO₄ + BaCl₂ → BaSO₄↓ + NaCl) 5. Oxidation = Oxygen Gain / Hydrogen Loss 6. Reduction = Oxygen Loss / Hydrogen Gain 👉 Trick: OIL RIG → Oxidation Is Loss, Reduction Is Gain (of electrons). --- 🌟 Super Quick Exam Hacks Burning, Cooking, Rusting, Photosynthesis, Digestion = Chemical Cutting, Melting, Boiling, Dissolving (reversible) = Physical Color change, gas formation, heat/light, precipitate = Always Chemical Reaction sign

This question may look very easy, but I’ve seen many students making mistakes in it. Always remember these two keywords:

👉 Burning = Chemical reaction 👉 Melting = Physical reaction

Now, in this question they are asking about burning, so the correct answer will be Chemical Reaction.