Doubtify – JEE Ki Taiyaari, Simple Bhasha Mein

  ❓ Question Dumas Method – Nitrogen % in 60 Sec! A quick, exam-oriented breakdown of how Dumas Method helps you find percentage of nitrogen in an organic compound using only the nitrogen gas collected . 📝 1️⃣ Dumas Method Concept Organic compound is heated strongly → Nitrogen present in compound converts into N₂ gas → This N₂ is collected over water and its volume, temperature, pressure are measured. ✔ No chemical titration ✔ 100% physical calculation ✔ Based on ideal gas equation 📝 2️⃣ Correcting the Pressure (MOST Important Step) Gas is collected over water , so total pressure = Pressure of dry N₂ + water vapour pressure. Corrected pressure: P N 2 = P total − P aq. tension​ Given: P total = 715  mmHg , P aq. tension = 15  mmHg So, P N 2 = 700  mmHg 📝 3️⃣ Ideal Gas Equation (Find moles of N₂) P V = n R T Convert units: P = 700  mmHg = 700 / 760  atm P = 700\ \text{mmHg} = 700/760\ \text{atm} V = 50  mL = 0.0...

  ❓ Question In Dumas' method , 292 mg of an organic compound released 50.0 mL of nitrogen gas (N₂) at 300 K and 715 mm Hg total pressure. Aqueous tension at 300 K = 15 mm Hg . Find the percentage composition of nitrogen (N) in the organic compound. (Nearest integer) 🖼️ Question Image ✍️ Short Solution Step 1 — Correct the gas pressure for water vapor Total pressure above the collected gas includes water vapor. The partial pressure of dry N₂ is: P N 2 = P total − P H 2 O = 715 − 15 = 700  mm Hg . Step 2 — Use ideal gas law to find moles of N₂ Use P V = n R T. Convert volume to litres:  V = 50.0  mL = 0.0500  L V = 50.0\ \text{mL} = 0.0500\ \text{L} . Use gas constant in mmHg·L units: R = 62.3637   L \ mmHg \ mol − 1 \ K − 1 . So n N 2 = P N 2   V R   T = 700 × 0.0500 62.3637 × 300 . Calculate numerator: 700 × 0.0500 = 35.0 700\times0.0500 = 35.0 . Denominator: 62.3637 × 300 = 18709.11 62.3637\times300 = 18709.11 . Thus n N 2 = 35...