Class 12 Chemistry Solution lect-05

📌 Class 12 Chemistry | Chapter 1: Solutions — Raoult's Law, Colligative Properties & Van 't Hoff Factor 🧪⚡Welcome back to Run Academy! 🎓 In today’s high-yield lecture, we continue our deep dive into Chapter 1: Solutions for Class 12 Chemistry. After covering concentration terms and Henry’s Law, we now master Vapor Pressure, Raoult’s Law, the 4 Colligative Properties, and Abnormal Molar Masses. This is one of the most critical sections for CBSE Board Exams, State Boards, and competitive exams like NEET & JEE. Let's break down the formulas, graphs, and numerical tricks step-by-step! 🚀📚 WHAT YOU WILL LEARN IN THIS VIDEO:🔹 1. Vapor Pressure & Raoult's Law• 💨 Vapor Pressure: Equilibrium pressure exerted by vapors above a liquid surface.• 📜 Raoult's Law for Volatile Liquids: Total pressure is the sum of partial pressures ($P_{\text{total}} = P_A^0 x_A + P_B^0 x_B$).• 🧊 Raoult's Law for Non-Volatile Solutes: Relative lowering of vapor pressure is equal to the mole fraction of the solute ($\frac{P_A^0 - P_A}{P_A^0} = x_B$).• 📊 Ideal vs. Non-Ideal Solutions: Positive and negative deviations from Raoult's Law with real examples (Ethanol+Acetone, Acetone+Chloroform).🔹 2. The Four Colligative Properties• 🔬 What are Colligative Properties? Properties that depend strictly on the number of solute particles, not their chemical nature.• 🌡️ 1. Relative Lowering of Vapor Pressure (RLVP): $\frac{\Delta P}{P_A^0} = x_B$• 📈 2. Elevation in Boiling Point ($\Delta T_b$):- Formula: $\Delta T_b = K_b \cdot m$- Understanding ebullioscopic constant ($K_b$) and temperature-enthalpy graphs.• 📉 3. Depression in Freezing Point ($\Delta T_f$):- Formula: $\Delta T_f = K_f \cdot m$- Cryoscopic constant ($K_f$) and real-life applications (e.g., adding ethylene glycol as antifreeze in car radiators).• 💧 4. Osmotic Pressure ($\pi$):- Formula: $\pi = C R T$ (or $\pi V = n R T$)- Isotonic, Hypertonic, and Hypotonic solutions, plus reverse osmosis (RO water purification).🔹 3. Abnormal Molar Mass & Van 't Hoff Factor ($i$)• ⚠️ Why do calculated molar masses sometimes mismatch? Due to association (dimerization/trimerization) or dissociation (ionization of salts like $\text{NaCl}$).• 🧮 Van 't Hoff Factor ($i$):- $i = \frac{\text{Normal Molar Mass}}{\text{Abnormal Molar Mass}} = \frac{\text{Observed Colligative Property}}{\text{Calculated Colligative Property}}$• 📝 Modified Colligative Equations: Integrating $i$ into formulas (e.g., $\Delta T_b = i \cdot K_b \cdot m$)💡 WHY SUBSCRIBE TO RUN ACADEMY?At Run Academy, we make Class 12 Chemistry simple, visual, and exam-oriented! 🎯👉 Don't forget to LIKE, SHARE, and SUBSCRIBE to support the channel and boost your board exam & competitive rank!🔔 Turn on Notifications so you never miss a lecture!💬 Having trouble with Van 't Hoff factor calculations or Raoult's law? Drop your doubts in the Comments below, and we'll reply!🏷️ HIGH-RANKING TAGS FOR YOUTUBE:#Class12Chemistry #SolutionsClass12 #RaoultsLaw #ColligativeProperties #VanTHoffFactor #RunAcademy #ChemistryClass12 #CBSEClass12Chemistry #ElevationInBoilingPoint #OsmoticPressure #NEETChemistry #JEEChemistry #NCERTClass12 #BoardExamPreparation2026