## Paaras Thakur is teaching live on Unacademy Plus

CLASS SOLUTIONS 12 KEY CONCEPTS JEE/NEET/AIIMS/CBSE

Concept Distribution in JEE (Main and Advanced) Topics Covered Year JEE (Advanced) JEE (Main) Vapour Pressure of Ideal Solutions, Colligative Properties of Dilute Solutions Vapour Pressure of Ideal Solutions Vapour Pressure of ldeal Solutions, Real Solutions Vapour Pressure of ldeal Solutions, Colligative Properties of Dilute Solutions Colligative Properties of Dilute Solutions, Molecular Weight Calculations Colligative Properties of Dilute Solutions 2007 Molecular Weight Calculations Colligative Properties of Dilute Solutions Solubility 2008 2009 2011 Colligative Properties of Dilute Solutions 2012 2013 2014 Colligative Properties of Dilute Solutions Vapour Pressure of ldeal Solutions Molecular Weight Calculations Vapour Pressure of Pure Solvents, Vapour Pressure of Ideal Solutions, Colligative Properties of Dilute Solutions Vapour Pressure of ldeal Solutions, Colligative Properties of Dilute Solutions, Molecular Weight Calculations Colligative Properties of Dilute Solutions, Solubility Molecular Weight Calculations 2015 Colligative Properties of Dilute Solutions 2016 Vapour Pressure of Ideal Solutions, Molecular Weight Calculations

Expressing Concen trak Soluhon aSs Per ce w/w) : weight ) Streudu Pex 100 maw Volume Percent as (yo) : Vlume fo ml

Mass by volume peron m/ PPM and PPR Lose solut dut Mole hachon 0 0 0 ve

O Molan one molar sou m lar Hu uo Take1me H 34.sq) and dissve repar Molau rm NaoH Solm 0

Ecample 21 Calculate the mole fraction of ethylene glycol (C2HO) in a solution containing 20% of C2H602 by mass. olution Assume that we have 100 g of solution (one can start with any amount of solution because the results obtained will be the same). Solution will contain 20 g of ethylene glycol and 80 g of water. Molar mass of C2H60,-12x 2 + 1 6 + 16 2-62 g mol-1 Moles of C2H62 g mol 20 g = 0.322 mol 80 g 18 g mol Moles of water- 4.444 mol moles of C2H6O2 moles of C HO moles of H O glycol- 262 2 0.322 mol 0.322 mol +4.444 mol 0.068 4.444 mol 0.932 ' water 0.322 mol 4.444 mol Mole fraction of water can also be calculated as: 1-0.068 = 0.932